Identification, characterization and expression of adipose differentiation-related protein (ADRP) gene and protein in ovaries of the giant tiger shrimp Penaeus monodon

In this study, the full length cDNA of adipose differentiation-related protein, a gene involved in neutral lipid accumulation that is important in oocyte maturation, of the giant tiger shrimp, Penaeus monodon (PmADRP) was identified and characterized. PmADRP was 1292 bp in length containing an ORF of 1107 bp corresponding to a polypeptide of 368 amino acids. PmADRP was abundantly expressed in ovaries but not in testes of P. monodon juveniles and broodstock or several tissues (e.g. intestine, eyestalk and gill) of P. monodon broodstock. The expression levels of PmADRP in ovaries of juvenile P. monodon were significantly induced following 5-HT administration at 48 h post treatment (P < 0.05). Quantitative real-time PCR illustrated that the PmADRP mRNA in ovaries of juveniles was lower than that of broodstock (P < 0.05). In intact broodstock, PmADRP was significantly up-regulated at early cortical rod (stage III) ovaries and after spawning (P < 0.05). Likewise, the expression level of PmADRP in early cortical rod and mature (IV) ovaries was significantly greater than that in previtellogenic (I) and vitellogenic (II) ovaries of eyestalk-ablated broodstock (P < 0.05). In situ hybridization indicated that PmADRP was localized in ooplasm of previtellogenic oocytes. The PmADRP protein was detected since the vitellogenic stage for intact broodstock and since the previtellogenic stage for eyestalk-ablated broodstock. Results suggested functionally important roles of PmADRP on oocyte and ovarian development of P. monodon.