RESUMEN

Processes of molecular innovation require tinkering and shifting in the function of existing genes. How this occurs in terms of molecular evolution at long evolutionary scales remains poorly understood. Here, we analyse the natural history of a vast group of membrane-associated molecular systems in Bacteria and Archaea-the type IV filament (TFF) superfamily-that diversified in systems involved in flagellar or twitching motility, adhesion, protein secretion, and DNA uptake. The phylogeny of the thousands of detected systems suggests they may have been present in the last universal common ancestor. From there, two lineages-a bacterial and an archaeal-diversified by multiple gene duplications, gene fissions and deletions, and accretion of novel components. Surprisingly, we find that the 'tight adherence' (Tad) systems originated from the interkingdom transfer from Archaea to Bacteria of a system resembling the 'EppA-dependent' (Epd) pilus and were associated with the acquisition of a secretin. The phylogeny and content of ancestral systems suggest that initial bacterial pili were engaged in cell motility and/or DNA uptake. In contrast, specialised protein secretion systems arose several times independently and much later in natural history. The functional diversification of the TFF superfamily was accompanied by genetic rearrangements with implications for genetic regulation and horizontal gene transfer: systems encoded in fewer loci were more frequently exchanged between taxa. This may have contributed to their rapid evolution and spread across Bacteria and Archaea. Hence, the evolutionary history of the superfamily reveals an impressive catalogue of molecular evolution mechanisms that resulted in remarkable functional innovation and specialisation from a relatively small set of components.

Asunto(s)

Citoesqueleto/genética , ADN/metabolismo , Transferencia de Gen Horizontal/genética , Proteínas de Filamentos Intermediarios/genética , Filamentos Intermedios/genética , Archaea/clasificación , Archaea/genética , Archaea/metabolismo , Bacterias/clasificación , Bacterias/genética , Bacterias/metabolismo , Adhesión Celular/genética , Citoesqueleto/metabolismo , ADN/genética , Evolución Molecular , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/metabolismo , Filamentos Intermedios/clasificación , Filamentos Intermedios/metabolismo , Movimiento , Filogenia , Transporte de Proteínas/genética

RESUMEN

The nuclear lamina is a protein meshwork associated with the inner side of the nuclear envelope contributing structural, signalling and regulatory functions. Here, I report on the evolution of an important component of the lamina, the lamin intermediate filament proteins, across the eukaryotic tree of life. The lamins show a variety of protein domain and sequence motif architectures beyond the classical α-helical rod, nuclear localisation signal, immunoglobulin domain and CaaX motif organisation, suggesting extension and adaptation of functions in many species. I identified lamin genes not only in metazoa and Amoebozoa as previously described, but also in other opisthokonts including Ichthyosporea and choanoflagellates, in oomycetes, a sub-family of Stramenopiles, and in Rhizaria, implying that they must have been present very early in eukaryotic evolution if not even the last common ancestor of all extant eukaryotes. These data considerably extend the current perception of lamin evolution and have important implications with regard to the evolution of the nuclear envelope.

Asunto(s)

Eucariontes/genética , Proteínas de Filamentos Intermediarios/genética , Laminas/genética , Animales , Análisis por Conglomerados , Biología Computacional/métodos , Evolución Molecular , Perfilación de la Expresión Génica , Proteínas de Filamentos Intermediarios/química , Proteínas de Filamentos Intermediarios/clasificación , Laminas/química , Dominios y Motivos de Interacción de Proteínas

RESUMEN

OBJECTIVE: To identify the type of the intermediate filament (IF) protein of Angiostrongylus cantonensis and analyze its tissue localization. METHODS: Recombinant pET-IF of antigen IF was expressed in E.coli with IPTG induction, and the expression products were purified by His.Bind column and identified for determining the type of the IF protein by Western blotting. Anti-IF antibody was prepared by multi-spot subcutaneous injection into mouse and used to detect the tissue slices of A. cantonensis by immunohistochemical analysis. RESULTS: The antigen IF were correctly expressed and purified, and identified as a keratin located in the intestine wall and cytoplusma. CONCLUSION: The antigen IF is distributed in the intestine wall of A. cantonensis.

Asunto(s)

Angiostrongylus cantonensis/citología , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/metabolismo , Angiostrongylus cantonensis/metabolismo , Animales , Núcleo Celular/metabolismo , Electroforesis en Gel de Poliacrilamida , Proteínas de Filamentos Intermediarios/genética , Proteínas de Filamentos Intermediarios/aislamiento & purificación , Transporte de Proteínas

RESUMEN

Intermediate filaments (IFs) are cytoskeletal structures that are crucial for maintaining the structural and mechanical integrity of cells and tissues. Intriguingly, a wide range of previously unknown nonmechanical roles for the IF cytoskeleton are emerging: Recent studies have linked IFs to the integration of signals related to the determination of cell size, the regulation of cell migration and cell survival, and the buffering of the effects of stress-activated kinases. The characteristic structural features and expression patterns of the different members of this diverse family of highly abundant proteins make them well suited to act as cell- and tissue-specific modifiers and organizers of signaling.

Asunto(s)

Proteínas de Filamentos Intermediarios/fisiología , Filamentos Intermedios/fisiología , Transducción de Señal/fisiología , Animales , Fenómenos Fisiológicos Celulares , Citoesqueleto/fisiología , Humanos , Proteínas de Filamentos Intermediarios/clasificación

RESUMEN

We have previously hypothesized that regeneration of axons after spinal cord injury in the lamprey may involve assembly and transport of neurofilaments (NFs) into the growing tip. A single NF, NF-180, has been cloned in this laboratory and until now was thought to be the only NF subunit in lamprey nervous system. However, homopolymerization of NF-180 has not been observed either in experiments on transfected cells or in self-assembly tests in vitro. Forty-three monoclonal antibodies designated as LCM series were generated previously against cytoskeletal proteins of the lamprey nervous system. Seven LCMs were NF specific, and five were keratin specific, as demonstrated by immunohistochemistry. In the present study, one antibody, LCM40, selectively labeled axons in immunohistochemical sections and recognized a single 50-kDa protein in Western blots. Other neuron-specific LCMs and anti-NF antibodies, e.g., LCM39, recognized a known NF subunit, NF-180. Two-dimensional (2-D) gel electrophoresis was employed to separate otherwise indistinguishable individual cytoskeletal proteins. Western blot analysis with an antibody (IFA) that selectively labels all known intermediate filaments indicated that this 50-kDa protein is an intermediate filament (IF). The new protein was incorporated into IF polymers in vitro. Immunoelectron microscopy confirmed that neuronal IFs contain this novel protein. These results suggest that the 50-kDa protein is a previously unrecognized neuronal IF subunit in the lamprey.

Asunto(s)

Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Neurofilamentos/aislamiento & purificación , Animales , Anticuerpos/clasificación , Anticuerpos/metabolismo , Axones/metabolismo , Axones/ultraestructura , Western Blotting/métodos , Proteínas del Citoesqueleto/metabolismo , Electroforesis en Gel Bidimensional/métodos , Regulación del Desarrollo de la Expresión Génica/fisiología , Inmunohistoquímica/métodos , Proteínas de Filamentos Intermediarios/inmunología , Lampreas , Larva , Microscopía Inmunoelectrónica/métodos , Peso Molecular , Proteínas de Neurofilamentos/clasificación , Proteínas de Neurofilamentos/inmunología , Mapeo de Interacción de Proteínas/métodos , Médula Espinal/metabolismo , Médula Espinal/ultraestructura

RESUMEN

To further characterize the interaction of cytoplasmic intermediate filament (cIF) proteins with supercoiled (sc)DNA, and to support their potential function as complementary nuclear matrix proteins, the type III IF proteins vimentin, glial fibrillary acidic protein, and desmin were analyzed for their capacities to interact with supercoiled plasmids containing a bent mouse gamma-satellite insert or inserts capable of non-B-DNA transitions into triplex, Z, and cruciform DNA, that is, DNA conformations typically bound by nuclear matrices. While agarose gel electrophoresis revealed a rough correlation between the superhelical density of the plasmids and their affinity for cIF proteins as well as cIF protein-mediated protection of the plasmid inserts from S1 nucleolytic cleavage, electron microscopy disclosed binding of the cIF proteins to DNA strand crossovers in the plasmids, in accordance with their potential to interact with both negatively and positively supercoiled DNA. In addition, the three cIF proteins were analyzed for their effects on eukaryotic DNA topoisomerases I and II. Possibly because cIF proteins interact with the same plectonemic and paranemic scDNA conformations also recognized by topoisomerases, but select the major groove of DNA for binding in contrast to topoisomerases that insert into the minor groove, the cIF proteins were able to stimulate the enzymes in their supercoil-relaxing activity on both negatively and positively supercoiled plasmids. The stimulatory effect was considerably stronger on topoisomerase I than on topoisomerase II. Moreover, cIF proteins assisted topoisomerases I and II in overwinding plasmid DNA with the formation of positive supercoils. Results obtained with the N-terminal head domain of vimentin harboring the DNA binding region and terminally truncated vimentin proteins indicated the involvement of both protein-DNA and protein-protein interactions in these activities. Based on these observations, it seems conceivable that cIF proteins participate in the control of the steady-state level of DNA superhelicity in the interphase nucleus in conjunction with such topoisomerase-controlled processes as DNA replication, transcription, recombination, maintenance of genome stability, and chromosome condensation and segregation.

Asunto(s)

ADN-Topoisomerasas de Tipo II/metabolismo , ADN-Topoisomerasas de Tipo I/metabolismo , ADN Superhelicoidal/metabolismo , Proteínas de Filamentos Intermediarios/metabolismo , Plásmidos/metabolismo , Animales , Secuencia de Bases , Bovinos , ADN Superhelicoidal/genética , ADN Superhelicoidal/ultraestructura , Desmina/metabolismo , Drosophila , Proteína Ácida Fibrilar de la Glía/metabolismo , Técnicas In Vitro , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/ultraestructura , Ratones , Microscopía Electrónica , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Plásmidos/genética , Plásmidos/ultraestructura , Unión Proteica , Porcinos , Vimentina/metabolismo

RESUMEN

The urochordate Ciona intestinalis is a well established system for embryological studies, and large scale EST sequences begin to emerge. We cloned five cytoplasmic intennediate filament (IF) cDNAs and made specific antibodies to the recombinant proteins. Self-assembly studies and immunofluorescence microscopy were used to study these proteins and their distribution. Confirming and extending previous studies in Styela, we found that Ciona protein IF-A is expressed in muscle and forms homopolymeric filaments while proteins IF-C and IF-D, which form only obligatory heteropolymeric filaments, resemble a keratin pair exclusively found in the entire epidermis. Protein IF-B and the new protein IF-F potentially reflect tunicate-specific IF proteins. They are found in the entire internal epithelia including the neural gland. We also extended the analysis to earlier developmental stages of Ciona. Protein IF-A is expressed in muscle from larval stages, whereas proteins IF-C and IF-D are found only in the tail epidermis. Protein IF-F is detected abundantly in the test cells of eggs, embryos and premetamorphic larvae. Our studies show that IF proteins could prove very useful markers in the study of cell fate determination in Ciona. They also support previous findings on the evolutionary relationships of different IF proteins. Non-vertebrate chordates have IF proteins which represent orthologs of vertebrate type I to III proteins, but also IF proteins that do not seem to fit into these classes. However, the intron positions of all tunicate IF genes are conserved with vertebrate type I to III genes, pointing to a common evolutionary origin.

Asunto(s)

Proteínas de Filamentos Intermediarios/genética , Proteínas de Filamentos Intermediarios/metabolismo , Urocordados/embriología , Urocordados/crecimiento & desarrollo , Secuencia de Aminoácidos , Animales , Biomarcadores , Regulación del Desarrollo de la Expresión Génica , Inmunohistoquímica , Proteínas de Filamentos Intermediarios/química , Proteínas de Filamentos Intermediarios/clasificación , Filamentos Intermedios/química , Filamentos Intermedios/metabolismo , Filamentos Intermedios/ultraestructura , Datos de Secuencia Molecular , Familia de Multigenes , Filogenia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Urocordados/citología , Urocordados/genética

Asunto(s)

Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/genética , Animales , Humanos , Proteínas de Filamentos Intermediarios/química , Proteínas de Filamentos Intermediarios/fisiología

RESUMEN

The intermediate filament network spreading from the cell periphery to the nucleus forms dynamic linkages between nuclear matrix, actin microfilaments, and the extracellular matrix. The six different types (types I-VI) of IF proteins consisting of nearly 50 different proteins form at least nine different kinds of filaments depending on the tissue types: keratins, lamins, vimentin, desmin, neurofilaments, peripherin, alpha-internexin, glial fibrillary acidic protein and nestin. Their tissue specific expression in normal cells and differential expression/assembly in neoplasia has been of immense value in tumor diagnosis. At the same time, recent in vitro studies point out that keratins, lamins and vimentin are subject to caspase-mediated proteolysis in an apoptosis-related manner. We reviewed the experimentally demonstrated P4-P1 motif specificities of caspases in the selection of substrates in the IF protein family. In addition, we provided clues to possible cleavage of additional IF proteins during programmed cell death, based on acceptable cut site motifs indicated by searches using the PIR protein sequence database. The present review concludes with presentation of evidence on the emerging roles of IFs in association with intermediate filament associated proteins in the dynamic remodeling of the cell during development of neoplastic phenotype and execution of apoptosis.

Asunto(s)

Apoptosis/fisiología , Proteínas de Filamentos Intermediarios/fisiología , Neoplasias/patología , Secuencia de Aminoácidos , Transformación Celular Neoplásica , Humanos , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/metabolismo , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Distribución Tisular

RESUMEN

The full length cDNA sequences of rat and mouse filensin are presented, as well as the structure of the rat filensin gene. This gene spanned 31 kb and included seven introns. The first six introns were conserved in position and phase with those found in the intermediate filament (IF) protein genes of the type II (type II keratin), type III (vimentin) and type V (lamin). The last intron of the filensin was unique. As none of the filensin intron positions coincided with those unique to type I, II or IV genes, it appears that filensin is most similar to type III genes. Comparison of the deduced amino acid sequences for rat and mouse filensin with those of cow and chick, and with other species of IF proteins, indicated the C-terminal non-alpha-helical tail domain of filensin to be one of the most divergent yet found in the vertebrate IF family. The tail domain had three conserved regions which are interrupted with two regions with lower identity. Two motifs, (1) PGDVPDGxxISKAF; and (2) KVEVVESIEKxxxxxIQTYEETxxIVET, were identified as sequences which were particularly highly conserved across species. Coassembly studies using CP49 and a physiologically derived 53 kDa-fragment of filensin showed the motif (2) was not required for filament assembly in vitro. These data strengthen the view that the C-terminal non-alpha-helical domain of filensin contributes in more than one way to filensin function in the lens.

Asunto(s)

Proteínas del Ojo/genética , Proteínas de Filamentos Intermediarios/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sitios de Unión , Clonación Molecular , ADN Complementario , Proteínas del Ojo/clasificación , Proteínas del Ojo/metabolismo , Humanos , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/metabolismo , Ratones , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Ratas , Ratas Sprague-Dawley , Homología de Secuencia de Aminoácido , Especificidad de la Especie

Asunto(s)

Proteínas de Filamentos Intermediarios , Familia de Multigenes/genética , Secuencia de Aminoácidos , Evolución Biológica , Diferenciación Celular , Humanos , Proteínas de Filamentos Intermediarios/biosíntesis , Proteínas de Filamentos Intermediarios/química , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/genética , Datos de Secuencia Molecular , Conformación Proteica

RESUMEN

We have isolated and characterized cDNAs that encode a protein expressed in the axons and growth cones of a subset of Xenopus embryonic neurons. The protein is also expressed in a subset of cells of the brain, including cells in even-numbered rhombomeres, the eye, and the heart. The sequence of the cDNA suggests that the protein belongs to a new class of neural-specific intermediate filaments. Both the RNA and the protein are expressed in the neurula and persist during embryogenesis in the brain, cranial nerves, and spinal cord. Because of the predicted structure of the protein, we have named it tanabin (from the Persian word for rope).

Asunto(s)

Proteínas de Drosophila , Embrión no Mamífero/metabolismo , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neuronas/metabolismo , Receptores de Superficie Celular , Xenopus laevis/embriología , Secuencia de Aminoácidos , Animales , Anticuerpos/inmunología , Anticuerpos/aislamiento & purificación , Axones/metabolismo , Secuencia de Bases , Clonación Molecular , Desarrollo Embrionario y Fetal , Hormonas de Insectos/inmunología , Hormonas de Insectos/metabolismo , Proteínas de Filamentos Intermediarios/genética , Glicoproteínas de Membrana/inmunología , Glicoproteínas de Membrana/metabolismo , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/genética , Neuronas/inmunología , ARN Mensajero/metabolismo , Distribución Tisular , Receptores Toll-Like , Proteínas de Xenopus

Asunto(s)

Proteínas de Filamentos Intermediarios/fisiología , Filamentos Intermedios/fisiología , Animales , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/genética , Familia de Multigenes

Asunto(s)

Proteínas de Filamentos Intermediarios/genética , Glicoproteínas de Membrana , Proteínas del Tejido Nervioso , Degeneración Retiniana/genética , Terminología como Asunto , Proteínas de Filamentos Intermediarios/clasificación , Mutación/genética , Periferinas

RESUMEN

Snap-frozen samples from 22 primitive neuroectodermal tumors (PNETs) primary in the central nervous system were studied with antibodies to synaptophysin, bombesin, somatostatin, substance P, vasoactive intestinal polypeptide, all classes of intermediate filaments, and desmoplakins I and II. Frozen sections were immunostained by the avidin-biotin peroxidase complex and indirect immunofluorescence microscopy methods. Selected cases were also studied by double and triple label immunofluorescence microscopy, and by two-dimensional gel electrophoresis and immunoblot analysis. We found that all 22 PNETs expressed synaptophysin extensively. Focal expression of 2 or more neuropeptides was noted in 10 samples studied. All PNETs expressed vimentin, 21 of 22 expressed glial filament protein (GFP), 16 of 22 expressed neurofilament proteins (NFP), 4 of 22 expressed desmin, and 3 of 22 expressed cytokeratins. In only one case were focal and questionable reactions with desmoplakin antibodies seen. Immunoblots confirmed the presence of desmin. Double and triple immunofluorescence revealed a number of antigenic coexpressions in individual cells including: synaptophysin with vimentin, GFP, NFP and desmin, vimentin-GFP, vimentin-NFP, vimentin-cytokeratin, vimentin-desmin and desmin-NFP; similarly, combinations of vimentin-GFP-NFP, vimentin-GFP-desmin, and vimentin-GFP-cytokeratin were found. The consistent expression of synaptophysin and 2 or more neuropeptides indicates that central nervous system PNETs have significant phenotypic features in common with neuroendocrine tumors. Their complex and variable intermediate filament complement patterns combined with their consistent expression of specific neuroendocrine differentiation markers, suggest that central nervous system PNETs comprise a distinct, albeit heterogeneous group of neoplasms.

Asunto(s)

Enfermedades del Sistema Nervioso Central/metabolismo , Proteínas de Filamentos Intermediarios/metabolismo , Proteínas de la Membrana/metabolismo , Neoplasias de Células Germinales y Embrionarias/metabolismo , Neuropéptidos/metabolismo , Sistemas Neurosecretores/metabolismo , Adolescente , Biomarcadores , Niño , Preescolar , Humanos , Inmunohistoquímica , Lactante , Recién Nacido , Proteínas de Filamentos Intermediarios/clasificación , Masculino , Proteínas del Tejido Nervioso/metabolismo , Sinaptofisina

RESUMEN

Compared with heteropolymeric assemblies of neurofilament (NF) triplet proteins in mammalian NFs, lamprey (Petromyzon marinus) NFs are homopolymers of 180 kDa subunits (NF180). We describe unique features of lamprey NF180 that distinguish it as a prototype of vertebrate NF subunits. These features may underlie key functions subserved by the earliest vertebrate NFs. Lamprey NF180 displays properties common to all intermediate filament (IF) proteins, but it also exhibits features that distinguish the mammalian triplet of NF subunits from all other IF proteins. For example, digestion of lamprey NF180 with chymotrypsin produces an insoluble 40 kDa core unit and releases a soluble fragment intermediate in size (140 kDa) to the carboxy-terminal (sidearm) extensions of the 2 high-molecular-weight (Mr) mammalian NF subunits. The core unit contains epitopes similar to those in the core of each mammalian NF triplet protein, while the soluble fragment contains other determinants similar to those in the sidearms of the 2 high-Mr mammalian NF polypeptides. Like these polypeptides, the immunological properties of some NF180 peripheral determinants were strongly affected by their phosphorylation state. Indeed, NF180 shares immunological similarities with the multiphosphorylation repeat domains in the high-Mr mammalian NF subunits. Further similarities with mammalian NF proteins include the preferential expression of poorly phosphorylated NF180 isoforms and of phosphate-dependent NF180 epitopes in axons of all sizes, and the restriction of nonphosphorylated NF180 isoforms to neuronal perikarya. In marked contrast to mammals, however, the most heavily phosphorylated isoforms of NF180 were expressed exclusively in large-diameter axons. We conclude that the single subunit forming lamprey NFs exhibits the essential features of mammalian NFs, i.e., a filament-forming core and a carboxy-terminal extension with a multiphosphorylation site. Further, the sharp restriction of heavily phosphorylated NF180 to large axons suggests that multiphosphorylation domains were acquired during evolution to permit larger axon diameters and faster conduction velocities.

Asunto(s)

Axones/metabolismo , Citoesqueleto/metabolismo , Proteínas de Filamentos Intermediarios/metabolismo , Filamentos Intermedios/metabolismo , Fosfatasa Alcalina/metabolismo , Animales , Encéfalo/metabolismo , Proteínas del Citoesqueleto/clasificación , Immunoblotting , Inmunoquímica , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/inmunología , Isomerismo , Lampreas , Peso Molecular , Proteínas de Neurofilamentos , Neuronas/metabolismo , Fosforilación , Ratas , Médula Espinal/metabolismo

RESUMEN

The principal subunits of neurofilaments (NFs) of immature cultured sympathetic neurons have apparent Mr of 68,000 and 145,000; a 200,000 Mr subunit is also present, but at comparatively low levels. These subunits are referred to as the low (NFL), middle (NFM), and high (NFH) Mr subunits, respectively. We studied the phosphorylation of NFL and NFM in these neurons in order to characterize the NFL and NFM isoforms generated by this important posttranslational modification. NFL resolved into a single spot in 2-dimensional gels, although 2 spots were occasionally observed. NFM typically resolved into 3 variants, termed NFM a, b, and c, in order of increasing mobility, but as many as 6 variants were detected in some gels. NFL and, to a much greater degree, NFM became labeled following incubation of intact neurons with 32P-PO4. Although all 3 major NFM variants became labeled, NFM a was the most heavily labeled, followed by NFM b, and then NFM c. Two observations suggest that the generation of these 3 NFM variants is due to their phosphorylation. First, treatment of NFs with phosphatase prior to analysis reduced NFM to a single spot or band that comigrated with NFM c; NFM a and b were completely eliminated. However, NFM c was not fully dephosphorylated because it still reacted with a monoclonal antibody (mAb) specific for a phosphate-dependent epitope on NFM. Second, NFM was recognized by 4 mAbs to distinctly different phosphorylated epitopes of NFM, which suggested that at least 4 distinct sites on NFM can be phosphorylated in cultured neurons. Explant cultures were used to study the phosphorylation of NFL and NFM in cell bodies and axons. In these cultures, a central cell body mass (CBM) 0.5 mm in diameter contains all of the cell bodies, while peripheral to the CBM is a halo of pure axons that extends for 4-6 mm. These cultures were incubated with 32P-PO4 and CBM and axon regions were analyzed separately. NFL became phosphorylated to a greater extent in the CBM than in axons. NFM also became labeled in the CBM and axons, although the relative labeling of NFM a, b, and c in these regions differed considerably from each other and also from the pattern observed in whole neurons (cell bodies plus neurites, see above).(ABSTRACT TRUNCATED AT 400 WORDS)

Asunto(s)

Axones/metabolismo , Compartimento Celular , Proteínas de Filamentos Intermediarios/metabolismo , Neuronas/metabolismo , Acetilación , Animales , Autorradiografía , Células Cultivadas , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Neurofilamentos , Monoéster Fosfórico Hidrolasas/farmacología , Fosforilación , Sistema Nervioso Simpático/citología , Factores de Tiempo

RESUMEN

Ninety four pulmonary neoplasms were examined immunocytochemically with two or three different monoclonal antibodies against the intermediate filament proteins cytokeratin, neurofilament, vimentin, and desmin. In normal tissues these have a different and non-overlapping distribution, and it is generally believed that tumours maintain the same pattern of expression as the tissues from which they arise. In this report, however, the coexpression of at least two (and less commonly three or four) different intermediate filaments was seen in 40% (37 of 94) of the cases of lung cancer. These results, especially if confirmed in other common types of human malignancy, have considerable implications for the use of anti-intermediate filament antibodies in diagnostic pathology.

Asunto(s)

Proteínas de Filamentos Intermediarios/análisis , Neoplasias Pulmonares/análisis , Adenocarcinoma/análisis , Anticuerpos Monoclonales , Carcinoma de Células Pequeñas/análisis , Carcinoma de Células Escamosas/análisis , Humanos , Proteínas de Filamentos Intermediarios/clasificación , Neoplasias Pulmonares/patología

RESUMEN

The mature enteric nervous system (ENS) is characterized by a degree of neuronal phenotypic diversity and independence of central nervous system control unequaled by any other region of the peripheral nervous system. Studies that have utilized the immunocytochemical demonstration of neurofilament protein and explanation of primordial gut with subsequent growth in culture have indicated that the neural crest precursors of enteric neurons are already committed to the neuronal lineage when they colonize the bowel; however, neuronal phenotypic expression occurs within the gut itself. It is likely that precursors able to give rise to each type of neuron found in the mature ENS are present among the earliest neural crest émigrés to reach the bowel. In mice a proximodistal wave of neuronal phenotypic expression occurs that does not appear to reflect the descent of neuronal precursors. This observation, the known plasticity of developing neural crest-derived neurons, and the demonstration of a persistent population of proliferating neuroblasts in the gut raise the possibility that enteric neuronal phenotypic expression is influenced by the enteric microenvironment.

Asunto(s)

Sistema Nervioso Autónomo/embriología , Intestinos/inervación , Animales , Sistema Nervioso Autónomo/crecimiento & desarrollo , Células Clonales , Proteínas de Filamentos Intermediarios/clasificación , Proteínas de Filamentos Intermediarios/inmunología , Cresta Neural/fisiología , Proteínas de Neurofilamentos , Neurotransmisores/fisiología , Fenotipo