RESUMEN
The present study investigated the prevalence of the polymorphisms in the exon 1 of the MBL2 gene in patients with tuberculosis at a hospital in northern Brazil, which is a regional reference for the treatment of the disease. The study group was composed of 167 patients with tuberculosis, 34 of which had the extra-pulmonary form of the disease, while the other 133 had the pulmonary type. The control group consists of 159 healthy individuals. Samples of DNA extracted from leucocytes were submitted to Polymerase Chain Reaction for the amplification of a 120-bp segment of exon 1 of the MBL2 gene. The distribution of allele and genotype frequencies varied little among the different groups, and it was not possible to establish any clear association between the variants of the MBL2 gene and the susceptibility to or clinical profile of tuberculosis infections in the population analyzed.
Asunto(s)
Lectina de Unión a Manosa/genética , Mycobacterium tuberculosis/crecimiento & desarrollo , Tuberculosis Pulmonar/genética , Tuberculosis/genética , Alelos , Brasil/epidemiología , Estudios de Casos y Controles , Exones , Femenino , Frecuencia de los Genes , Genotipo , Humanos , Masculino , Lectina de Unión a Manosa/clasificación , Isoformas de Proteínas/clasificación , Isoformas de Proteínas/genética , Tuberculosis/diagnóstico , Tuberculosis/epidemiología , Tuberculosis/microbiología , Tuberculosis Pulmonar/diagnóstico , Tuberculosis Pulmonar/epidemiología , Tuberculosis Pulmonar/microbiologíaRESUMEN
Lipins constitute a novel family of Mg(2+)-dependent phosphatidate phosphatases that catalyze the dephosphorylation of phosphatidic acid to yield diacylglycerol, an important intermediate in lipid metabolism and cell signaling. Whereas a single lipin is detected in less complex organisms, in mammals there are distinct lipin isoforms and paralogs that are differentially expressed among tissues. Compatible with organism tissue complexity, we show that the single Drosophila Lpin1 ortholog (CG8709, here named DmLpin) expresses at least three isoforms (DmLpinA, DmLpinK and DmLpinJ) in a temporal and spatially regulated manner. The highest levels of lipin in the fat body, where DmLpinA and DmLpinK are expressed, correlate with the highest levels of triacylglycerol (TAG) measured in this tissue. DmLpinK is the most abundant isoform in the central nervous system, where TAG levels are significantly lower than in the fat body. In the testis, where TAG levels are even lower, DmLpinJ is the predominant isoform. Together, these data suggest that DmLpinA might be the isoform that is mainly involved in TAG production, and that DmLpinK and DmLpinJ could perform other cellular functions. In addition, we demonstrate by immunofluorescence that lipins are most strongly labeled in the perinuclear region of the fat body and ventral ganglion cells. In visceral muscles of the larval midgut and adult testis, lipins present a sarcomeric distribution. In the ovary chamber, the lipin signal is concentrated in the internal rim of the ring canal. These specific subcellular localizations of the Drosophila lipins provide the basis for future investigations on putative novel cellular functions of this protein family.
Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimología , Regulación del Desarrollo de la Expresión Génica , Monoéster Fosfórico Hidrolasas/metabolismo , Isoformas de Proteínas/metabolismo , Fracciones Subcelulares/enzimología , Empalme Alternativo , Secuencia de Aminoácidos , Animales , Proteínas de Drosophila/clasificación , Proteínas de Drosophila/genética , Drosophila melanogaster/anatomía & histología , Drosophila melanogaster/fisiología , Femenino , Masculino , Datos de Secuencia Molecular , Proteínas Nucleares/clasificación , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Ovario/citología , Ovario/metabolismo , Monoéster Fosfórico Hidrolasas/clasificación , Monoéster Fosfórico Hidrolasas/genética , Filogenia , Isoformas de Proteínas/clasificación , Isoformas de Proteínas/genética , Alineación de Secuencia , Distribución Tisular , Triglicéridos/metabolismoRESUMEN
The heterogeneous nuclear ribonucleoproteins (hnRNPs) comprise a large family of proteins that play important roles in telomere biogenesis, DNA repair, cellular signaling, and the regulation of expression at both the transcriptional and translational levels. One of the most extensively studied hnRNP family members, hnRNP K, has been implicated in a variety of processes, including chromatin remodeling, transcription, splicing, and translation events. In this study, we analyzed processed HNRPK pseudogenes (HNRPK psi1-psi4) and coding sequences. HNRPK pseudogenes are apparently nonfunctional, and psi1 might correspond to transcripts from an ancestral gene. Phylogenetic and sequence analyses suggest that HNRP genes arose by duplication, and that new structural and sequence features expanded the functions of hnRNPs. The expression analysis of hnRNP K isoforms showed that isoform a is expressed in normal testis and in non-small cell lung cancer (NCI-H1155 NSCLC cell line), although the shorter isoform (isoform b) is expressed in different tumor cell lines (IM9 B-lymphoblastoid, Hs578T human breast cancer epithelial, T98G human glioma cell lines). Using molecular modeling, we obtained KH1 and KH3 models, which pointed to important residues for DNA-protein binding and no structural differences between isoforms a and b. To our knowledge, this is the first phylogenetic study including vertebrate HNRP genes and HNRPK pseudogenes, and the first report comparing the KH1 and KH3 domains of isoforms a and b of the hnRNP K protein. New investigations in tumor samples must be done to validate the differential expression observed here. The results shown are important because the hnRNP K protein might represent a new target for pharmacologic intervention in virus replication and cancer.
Asunto(s)
Genoma Humano/genética , Seudogenes/genética , Ribonucleoproteínas/química , Ribonucleoproteínas/genética , Transcripción Genética , Secuencia de Aminoácidos , Secuencia de Bases , Secuencia Conservada , Ribonucleoproteína Heterogénea-Nuclear Grupo K , Humanos , Datos de Secuencia Molecular , Filogenia , Conformación Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/clasificación , Isoformas de Proteínas/genética , Ribonucleoproteínas/clasificación , Células Tumorales CultivadasRESUMEN
The TLE genes constitute a family of important transcriptional co-repressors involved in many cellular processes. We found evidence of alternatively spliced mRNAs for human TLE1-4 containing premature stop codons, thus encoding putative shortened proteins. Microarray experiments and Real-time RT-PCR assays showed that alternatively spliced isoforms of TLE1, TLE2 an d TLE3 were preferentially expressed in prostate in comparison to liver and kidney tissues. We identified by orientation-specific R T-PCR an antisense partially intronic non-coding RNA that overlaps a novel exon of the TLE3 gene, raising the possibility of regulation of alternative splicing by this non-coding transcript. The alternatively spliced isoform of TLE3 was up-regulated (6- to 17-fo ld) in prostate tumors in comparison to matched non-tumor adjacent tissue from 7 out of 11 (64%) patients and in four prostate tumor cell lines in comparison to a normal prostate cell line. These results demonstrate that different isoforms of TLE genes are commonly transcribed in human tissues and suggest that TLE3 could be involved in prostate cancer development.
Asunto(s)
Regulación Neoplásica de la Expresión Génica/genética , Neoplasias de la Próstata/genética , Empalme del ARN/genética , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Regulación hacia Arriba/genética , Línea Celular Tumoral , Humanos , Riñón/metabolismo , Hígado/metabolismo , Masculino , Especificidad de Órganos , Isoformas de Proteínas/clasificación , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Represoras/clasificaciónRESUMEN
Protein kinase C (PKC) is a family of serine/threonine kinases that regulate many different cellular processes such as cell growth and differentiation in eukaryotic cells. Using specific polyclonal antibodies raised against mammalian PKC isoforms, it was demonstrated here for the first time that Giardia duodenalis expresses several PKC isoforms (beta, delta, epsilon, theta and zeta). All PKC isoforms detected showed changes in their expression pattern during encystment induction. In addition, selective PKC inhibitors blocked the encystment in a dose-dependent manner, suggesting that PKC isozymes may play important roles during this differentiation process. We have characterized here the only conventional-type PKC member found so far in Giardia, which showed an increased expression and changes in its intracellular localization pattern during cyst formation. The purified protein obtained by chromatography on DEAE-cellulose followed by size-exclusion chromatography, displayed in vitro kinase activity using histone HI-IIIS as substrate, which was dependent on cofactors required by conventional PKCs, i.e., phospholipids and calcium. An open reading frame in the Giardia Genome Database that encodes a homolog of PKCbeta catalytic domain was identified and cloned. The expressed recombinant protein was also recognized by a mammalian anti-PKCbeta antibody and was referred as giardial PKCbeta on the basis of all these experimental evidence.
Asunto(s)
Giardia/enzimología , Giardia/fisiología , Isoformas de Proteínas/clasificación , Proteína Quinasa C/clasificación , Animales , Diferenciación Celular , Isoformas de Proteínas/genética , Isoformas de Proteínas/aislamiento & purificación , Proteína Quinasa C/química , Proteína Quinasa C/metabolismo , Proteína Quinasa C betaRESUMEN
Uncoupling mitochondrial proteins (UCPs) belong to a discrete family within the mitochondrial anion carrier superfamily. Several uncoupling protein types have been found in mitochondria from mammals and plants, as well as in fishes, fungi, and protozoa. Mammalian UCPs and plant uncoupling proteins (PUMPs) form five distinct subfamilies. Only subfamily III contains both plant and animal uncoupling proteins, as well as UCPs from primitive eukaryotic organisms, which suggest that this group may represent an ancestral cluster from which other UCPs/PUMPs may have evolved. Genetic data indicate that UCPs/PUMPs are regulated at the transcriptional, post-transcriptional, and translational levels. Tissue/organ- and stress-specific gene expression suggests that UCPs/PUMPs are involved in the general balance of basic energy expenditure, protection against reactive oxygen species, and thermogenesis. Finally, the simultaneous occurrence of PUMP and alternative oxidase, another energy-dissipating system in plant mitochondria, raises the question of their response to biotic and abiotic stress at the transcriptional and functional levels.