[
DNA Seq,
2001]
Many insects survive adverse climatic conditions in a dormant state known as diapause. In this study, we identified and sequenced several mRNAs in diapausing Aedes triseriatus mosquito embryos. Using reverse-transcription PCR and 5'' RACE, we identified a 995-nucleotide cDNA that encodes a 259-amino acid protein of unknown function. This putative protein displays strong sequence similarity to Drosophila melanogaster (95%), human (87%), Caenorhabditis elegans (86%) and yeast (81%) counterparts. The second identified full-length cDNA consists of 624 nucleotides and encodes a 174-amino acid protein of unknown function. This putative protein displays significant sequence similarity to D. melanogaster (68%), human (59%), plant (57%) and yeast (49%) counterparts. We also detected a number of cDNA fragments that exhibited significant sequence similarity to a mitochondrial cytochrome C oxidase subunit, human N33 protein (a potential human prostate tumor suppressor), 18S and 28S ribosomal RNAs, protein disulfide-isomerase, and guanine nucleotide-binding protein.
[
BMC Genomics,
2008]
ABSTRACT: BACKGROUND: Much of the morphological diversity in eukaryotes results from differential regulation of gene expression in which transcription factors (TFs) play a central role. The nematode Caenorhabditis elegans is an established model organism for the study of the roles of TFs in controlling the spatiotemporal pattern of gene expression. Using the fully sequenced genomes of three Caenorhabditid nematode species as well as genome information from additional more distantly related organisms (fruit fly, mouse, and human) we sought to identify orthologous TFs and characterized their patterns of evolution. RESULTS: We identified 988 TF genes in C. elegans, and inferred corresponding sets in C. briggsae and C. remanei, containing 995 and 1093 TF genes, respectively. Analysis of the three gene sets revealed 652 3-way reciprocal ''best hit'' orthologs (nematode TF set), approximately half of which are zinc finger (ZF-C2H2 and ZF-C4/NHR types) and HOX family members. Examination of the TF genes in C. elegans and C. briggsae identified the presence of significant tandem clustering on chromosome V, the majority of which belong to ZF-C4/NHR family. We also found evidence for lineage-specific duplications and rapid evolution of many of the TF genes in the two species. A search of the TFs conserved among nematodes in Drosophila melanogaster, Mus musculus and Homo sapiens revealed 150 reciprocal orthologs, many of which are associated with important biological processes and human diseases. Finally, a comparison of the sequence, gene interactions and function indicates that nematode TFs conserved across phyla exhibit significantly more interactions and are enriched in genes with annotated mutant phenotypes compared to those that lack orthologs in other species. CONCLUSION: Our study represents the first comprehensive genome-wide analysis of TFs across three nematode species and other organisms. The findings indicate substantial conservation of transcription factors even across distant evolutionary lineages and form the basis for future experiments to examine TF gene function in nematodes and other divergent phyla.