RESUMEN
cDNA microarray technology has been increasingly used to monitor global gene expression patterns in various tissues and cell types. However, applications to mammalian development have been hampered by the lack of appropriate cDNA collections, particularly for early developmental stages. To overcome this problem, a PCR-based cDNA library construction method was used to derive 52,374 expressed sequence tags from pre- and peri-implantation embryos, embryonic day (E) 12.5 female gonad/mesonephros, and newborn ovary. From these cDNA collections, a microarray representing 15,264 unique genes (78% novel and 22% known) was assembled. In initial applications, the divergence of placental and embryonic gene expression profiles was assessed. At stage E12.5 of development, based on triplicate experiments, 720 genes (6.5%) displayed statistically significant differences in expression between placenta and embryo. Among 289 more highly expressed in placenta, 61 placenta-specific genes encoded, for example, a novel prolactin-like protein. The number of genes highly expressed (and frequently specific) for placenta has thereby been increased 5-fold over the total previously reported, illustrating the potential of the microarrays for tissue-specific gene discovery and analysis of mammalian developmental programs.
Asunto(s)
Embrión de Mamíferos/metabolismo , Regulación del Desarrollo de la Expresión Génica , Genoma , Placenta/metabolismo , Proteínas Gestacionales/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Cartilla de ADN , ADN Complementario , Femenino , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Embarazo , Proteínas Gestacionales/química , Homología de Secuencia de AminoácidoRESUMEN
Targeted sequencing of the mouse t-complex has started with a 176-kb, gene-rich BAC localized with six PCR-based markers in inversion 2/3 of the highly duplicated region. The sequence contains 11 genes recovered primarily as cDNAs from early embryonic collections, including Igfals (previously placed on chromosome 17), Nubp2 (a fully characterized gene), Jsap1 (a JNK-binding protein), Rsp29 (the mouse homologue of the rat gene), Ndk3 (a nucleoside diphosphate kinase), and six additional putative genes of unknown function. With 50% GC content, 75% of the DNA transcribed, and one gene/16.0 kb (on average), the region may qualify as one of the most gene-dense segments in the mouse genome and provides candidates for dosage-sensitive phenotypes and mouse embryonic lethals mapped to the vicinity.
Asunto(s)
ADN/genética , Familia de Multigenes/genética , Animales , Proteínas Portadoras/genética , Cromosomas Bacterianos/genética , Islas de CpG/genética , ADN Complementario/genética , Etiquetas de Secuencia Expresada , Regulación de la Expresión Génica de las Plantas , Glicoproteínas/genética , Humanos , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/genética , Proteínas Quinasas JNK Activadas por Mitógenos , Ratones , Proteínas Quinasas Activadas por Mitógenos/genética , Datos de Secuencia Molecular , Nucleósido-Difosfato Quinasa/genética , Isoformas de Proteínas/genética , Ratas , Homología de Secuencia de Ácido Nucleico , Tioléster Hidrolasas/genéticaRESUMEN
Little is known about gene action in the preimplantation events that initiate mammalian development. Based on cDNA collections made from each stage from egg to blastocyst, 25438 3'-ESTs were derived, and represent 9718 genes, half of them novel. Thus, a considerable fraction of mammalian genes is dedicated to embryonic expression. This study reveals profound changes in gene expression that include the transient induction of transcripts at each stage. These results raise the possibility that development is driven by the action of a series of stage-specific expressed genes. The new genes, 798 of them placed on the mouse genetic map, provide entry points for analyses of human and mouse developmental disorders.
Asunto(s)
Desarrollo Embrionario/genética , Expresión Génica , Animales , Mapeo Cromosómico , ADN Complementario , Etiquetas de Secuencia Expresada , Femenino , Biblioteca de Genes , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , EmbarazoRESUMEN
Two novel mouse genes and one novel human gene that define distinctive eukaryotic nucleotide-binding proteins (NUBP) and are related to the mrp gene of prokaryotes are characterized. Phylogenetic analyses of the genes, encoding a short form (Nubp2) and a long form (Nubp1) of NUBP, clearly establish them as a new NUBP/MRP gene family that is well conserved throughout phylogeny. In addition to conserved ATP/GTP-binding motifs A (P-loop) and A', members of this family share at least two highly conserved sequence motifs, NUBP/MRP motifs alpha and beta. Only one type of NUBP/MRP gene has been observed thus far in prokaryotes, but there are two types in eukaryotes. One group includes mouse Nubp1, human NBP, yeast NBP35, and Caenorhabditis elegans F10G8.6 and is characterized by a unique N-terminal sequence with four cysteine residues that is lacking in the other group, which includes mouse Nubp2, human NUBP2, and yeast YIA3w. Northern blot analyses of the two mouse genes show distinctive patterns consistent with this classification. Mouse Nubp2 is mapped to the t-complex region of mouse Chromosome 17, whereas Nubp1 is mapped to the proximal region of mouse Chromosome 16. Interestingly, both regions are syntenic with human chromosome 16p13.1-p13.3, suggesting that a chromosomal breakage between Nubp2 and Nubp1 probably occurred during the evolution of mouse chromosomes.