Characterization and Expression of Cytochrome b5 Gene and Protein in Ovaries of Giant Tiger Shrimp Penaeus monodon

Abstract

The full-length transcript of cytochrome b5 (PmCytb5) in the giant tiger shrimp (Penaeus monodon) was characterized. It was 1539 bp with an open reading frame (ORF) of 432 bp deducing to 143 amino acids. The deduced PmCytb5 protein contained predicted cytochrome b5-like heme/steroid binding domain (Cytb5, positions 17-91) and a transmembrane domain (positions 120-139). In non-ablated wild adults, PmCytb transcript was significantly increased in mature ovaries while it was earlier upregulated in late vitellogenic stage in eyestalk-ablated shrimp (P<0.05). Progesterone injection (0.1 μg/g) induced the expression of PmCytb5 at 48 hours post injection (hpi, P<0.05) but serotonin (50 μg/g) did not alter its expression (P>0.05) in domesticated adults. The cytoplasmic PmCytb5 protein was upregulated from immature ovaries in the early vitellogenic stage and comparably expressed in subsequent stages in non-ablated wild broodstock. In eyestalk-ablated wild broodstock, a similar expression profile was observed but its expression was further increased in late vitellogenic, and mature stages. The membrane PmCytb5 protein was upregulated in late vitellogenic and mature stages in the former but expressed at a similar level in different ovarian stages in eyestalk-ablated broodstock. Results suggested the important role of PmCytb5 in ovarian development of P. monodon.