title: Molecular characterization of the DDX3Y gene and its homologs in cattle.
abstract: DDX3Y (also known as DBY) is a member of the DEAD box protein family, which is involved in ATP-dependent RNA unwinding, needed in a variety of cellular processes including splicing, ribosome biogenesis and RNA degradation. In the human, DDX3Y is located in the AZFa interval in the Y chromosome. Deletion of the AZFa region has been shown to disrupt spermatogenesis, causing subfertility and infertility in otherwise healthy men. Here, we report the characterization of the bovine (b) DDX3Y gene and its homologs DDX3X and PL10. We found 2 transcripts for the bDDX3Y (bDDX3Y-L and -S), which correspond to the long and short transcripts of the human DDX3Y and mouse Ddx3y gene. The 2 transcripts are identical except for a 3-bp (AGT) insertion at the position of nt 2025 and an expanded 3'UTR (nt 2155-2769) in bDDX3Y-L. The bDDX3Y-S encodes a peptide of 660 amino acids (aa), while the bDDX3Y-L encodes a peptide of 661 aa as the result of an additional serine (S) insertion at the position of aa 634. Both bDDX3Y isoforms contain the conserved DEAD-box motif. The bDDX3Y is composed of 17 exons. The homologous gene on the X chromosome, bDDX3X, is highly conserved to the Y-copy at mRNA (83%) and protein (88%) levels as well as in the genomic structure. The autosomal copy, bPL10, mapped on BTA15, is a processed pseudogene with a similarity of 88.1% to bDDX3Y and 93.7% to bDDX3X mRNA, suggesting that PL10 is a retroposon of DDX3X. RT-PCR analyses showed that bDDX3Y-L, -S, bDDX3X and bPL10 were all widely expressed with predominant expression in testis and brain. Testicular section in situ hybridization revealed that sense and anti-sense RNAs of bDDX3Y-L, -S, and bDDX3X were expressed in interstitial cells. These results together with the finding that the pseudogene bPL10 is transcriptionally active in this study provide a basis for further investigating the DDX3 gene function in spermatogenesis, male fertility and gene evolution in mammals.
authors.affiliation: Department of Dairy and Animal Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA 16802, USA. wul12@psu.edu
authors.forename: W-S
authors.initials: WS
authors.lastname: Liu
authors.forename: A
authors.initials: A
authors.lastname: Wang
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.forename: T-C
authors.initials: TC
authors.lastname: Chang
authors.forename: E
authors.initials: E
authors.lastname: Landrito
authors.forename: H
authors.initials: H
authors.lastname: Yasue
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D002417:Cattle / Q000235:genetics*; D041321:Chromosomes, Human, X; D017124:Conserved Sequence; D053487:DEAD-box RNA Helicases / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008297:Male; D051379:Mice; D015778:Minor Histocompatibility Antigens; D008969:Molecular Sequence Data; D009928:Organ Specificity; D016415:Sequence Alignment; D013737:Testis / Q000201:enzymology; D014158:Transcription, Genetic; D014960:X Chromosome
chemical_list: D015778:Minor Histocompatibility Antigens; C492034:DDX3Y protein, human; D053487:DEAD-box RNA Helicases