A novel DDX5 gene in the freshwater crayfish Cherax  quadricarinatus is highly expressed during ontogenesis and spermatogenesis.
The freshwater crayfish Cherax quadricarinatus,  originally from Australia, is an invasive species that is also widely used in  aquaculture. DEAD-box helicase family genes are found throughout evolution and  encode RNA-binding proteins. The human DDX5 (p68) is important for normal cell  growth, differentiation and proliferation. We identified a C.  quadricarinatus homolog of DDX5 (Cq-DDX5); the temporal expression of  Cq-DDX5 mRNA transcripts was measured during early ontogenesis, during  spermatogenesis, during testes development, and during the annual cycle. The  Cq-DDX5 cDNA comprises 2258 nucleotides, with an open reading frame of 1569 bp,  encoding 522 amino acid residues. The deduced amino acid sequence of Cq-DDX5  has a 53 to 90% similarity to DDX5 of other eukaryotic species. mRNA  transcripts of Cq-DDX5 were detected in all tissues, with high levels in the  gonads. The DDX5 expression was highest in the nauplii stage, during early  ontogenesis and during testes development. In adult testes, transcripts  appeared at significantly higher levels in the prespawning and spawning phase  than in the post-spawning or regressed phase. Eyestalk ablation resulted in  upregulation of Cq-DDX5 in adult male gonads in a time-dependent manner, with a  peak at about 12 days. We conclude that the Cq-DDX5 gene plays an important  role in early ontogenesis and spermatogenesis, with a crucial reproductive  function in germ cell differentiation in these invertebrates.
School of Life Science, East China Normal University, Shanghai, China.
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D000595:Amino Acid Sequence; D000818:Animals; D003400:Astacoidea / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D002454:Cell Differentiation; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D006066:Gonads / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment; D013091:Spermatogenesis; D013737:Testis
D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; C506749:Ddx5 protein, human; D053487:DEAD-box RNA Helicases