Cytochrome P450 (CYP) superfamily is one of the membership largest and function most diverse protein superfamily recogniozed among living beings. Members of this superfamily were further assigned to different families and subfamilies based on their amino acid similarities. According to their phylogenetic relationships, the CYP genes which likely diverged from common ancestor gene and may share common functions were grouped into one clan. Widely distributing scallops are a group of the most conspicuous bivalve; however the studies on their CYP is acarce. In this study, we searched the genome and expressed sequence tags of Zhikong scallop (Chlamys farreri) for CYP genes. In total, 88 non-redundant CYP were identified, which were homed in 13 CYPs gene families. Phylogenetic analysis divided these genes into 4 CYP clans. As in deuterostomes, Clan 2 was the largest, which contained 33 genes belonging to CYP1, CYP2, CYP17 and CYP356 families. Clan 3 contgained 19 genes belonging to CYP3, CYP5 and CYP30 families. Clan 4 contained 23 genes, all belonging to CYP4 family. The mitochondrial CYP clan contained 9 genes belonging to CYP10 and CYP24 families. In comparison, protostomes (C. farreri, D. pluex, D. melanogaster) contained more CYP genes than deuterostomes (S. purpuratus and vertebrates) in Clan 2 but less genes in Clan 3 and Clan 4. Our findings will aid to deciphering CYP function and evolution in scallops and bivalves.
The Sox proteins play critical roles during the development of animals,including sex determination and central nervous system development.In this study,the SoxB2 gene was cloned from a mollusk,the Zhikong scallop(Chlamys farreri),and characterized with respect to phylogeny and tissue distribution.The full-length cDNA and genomic DNA sequences of C.farreri SoxB2(CfSoxB2) were obtained by rapid amplification of cDNA ends and genome walking,respectively,using a partial cDNA fragment from the highly conserved DNA-binding domain,i.e.,the High Mobility Group(HMG) box.The full-length cDNA sequence of CfSoxB2 was 2 048 bp and encoded 268 amino acids protein.The genomic sequence was 5 551 bp in length with only one exon.Several conserved elements,such as the TATA-box,GC-box,CAAT-box,GATA-box,and Sox/sry-sex/testis-determining and related HMG box factors,were found in the promoter region.Furthermore,real-time quantitative reverse transcription PCR assays were carried out to assess the mRNA expression of CfSoxB2 in different tissues.SoxB2 was highly expressed in the mantle,moderately in the digestive gland and gill,and weakly expressed in the gonad,kidney and adductor muscle.In male and female gonads at different developmental stages of reproduction,the expression levels of CfSoxB2 were similar.Considering the specific expression and roles of SoxB2 in other animals,in particular vertebrates,and the fact that there are many pallial nerves in the mantle,cerebral ganglia in the digestive gland and gill nerves in gill,we propose a possible essential role in nervous tissue function for SoxB2 in C.farreri.
