|Van Tassell, Curtis|
Submitted to: Biomed Central (BMC) Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 23, 2005
Publication Date: November 23, 2005
Citation: Harhay, G.P., Sonstegard, T.S., Keele, J.W., Heaton, M.P., Clawson, M.L., Snelling, W.M., Wiedmann, R.T., Van Tassell, C.P., Smith, T.P. 2005. Characterization of 954 bovine full-CDS cDNA sequences. Biomed Central (BMC) Genomics 6:166 (11 pp). Interpretive Summary: This paper describes the largest freely accessible public resource for experimentally determined complete bovine message (mRNA) sequences, the biomolecules carrying the complete “blueprints” for bovine protein creation. Previous bovine mRNA resources were based on bovine sequences that were only partially determined, causing uncertainty in bovine functional genomic studies as well as in bovine genome assembly. The completely determined mRNA sequences presented in this paper make studies of bovine protein function feasible, and facilitate the ongoing bovine genome assembly.
Technical Abstract: Genome assemblies rely on the existence of transcript sequence to stitch together contigs, verify assembly of whole genome shotgun reads, and annotate genes. Functional genomics studies also rely on transcript sequence to create expression microarrays or interpret digital tag data produced by methods such as Serial Analysis of Gene Expression (SAGE). Transcript sequence can be predicted based on reconstruction from overlapping expressed sequence tags (EST) that are obtained by single-pass sequencing of random cDNA clones, but these reconstructions are prone to errors caused by alternative splice forms, transcripts from gene families with related sequences, and expressed pseudogenes. The most useful transcript sequences are derived by complete insert sequencing of clones containing the entire length, or at least the full protein coding sequence (CDS) portion, of the source mRNA. While the bovine genome sequencing initiative is nearing completion, there is currently a paucity of bovine full-CDS mRNA and protein sequence data to support bovine genome assembly and functional genomics studies. Consequently, the production of high-quality bovine full-CDS cDNA sequences will enhance the bovine genome assembly and functional studies of bovine genes and gene products. The goal of this investigation was to identify and characterize the full-CDS sequences of bovine transcripts from clones identified in non-full-length enriched cDNA libraries. In contrast to several recent full-length cDNA investigations, these full-CDS cDNAs were selected, sequenced, and annotated without the benefit of the target organism’s genomic sequence, by using comparison of bovine EST sequence to existing human mRNA to identify likely full-CDS clones for full-length insert clone (FLIC) sequencing. The predicted bovine protein lengths, 5’ UTR lengths, and Kozak consensus sequences from 954 bovine FLIC sequences (bFLICs; average length 1713 nt, representing 762 distinct loci) are all consistent with previously sequenced mammalian full-length transcripts. In most cases, the bFLICs span the entire CDS of the genes, providing the basis for creating predicted bovine protein sequences to support proteomics and comparative evolutionary research as well as functional genomics and genome annotation. The results demonstrate the utility of the comparative approach in obtaining predicted protein sequences in other species.