Expression levels of RuvBL2 during ovarian development and association between its single nucleotide polymorphism (SNP) and growth of the giant tiger shrimp Penaeus monodon

Polymorphism of an ATP-dependent DNA helicase gene, RuvB-like 2 was examined in correlation with body weight and its expression during ovarian development of the giant tiger shrimp (Penaeus monodon). The full-length cDNA of P. monodon RuvB-like 2 (Pm-RuvBL2) was 3791 bp containing an ORF of 1392 bp corresponding to a polypeptide of 463 amino acids. Polymorphism of the amplified Pm-RuvBL2 gene segment (484 bp containing an intron of 259 bp) was initially examined in wild P. monodon (n = 15) by single strand conformational polymorphism (SSCP) analysis. Subsequently, correlation between Pm-RuvBL2 genotypes and the body weight of P. monodon was tested using commercially cultivated shrimp from the same pond (approximately 3 months old, average BW = 17.39 ± 4.36 g, n = 359). Disregarding sexes, the body weight of the shrimp carrying genotypes A (average BW = 19.277 ± 3.640 g, n = 37) and B (average BW = 19.293 ± 4.548 g, n = 79) was significantly greater than that of the shrimp carrying C (average BW = 16.528 ± 3.847 g, n = 93) and D (average BW = 16.365 ± 4.378 g, n = 124) genotypes. One exonic (G-A81) and two intronic (A-T196 and G-T248) SNPs corresponding to ATG, A[T/A]G, GAG and GAT for respective SSCP genotypes were found. Pm-RuvBL2 was more abundantly expressed in ovaries than testes and other tissues of P. monodon broodstock (P < 0.05). The relative expression levels of Pm-RuvBL2 in ovaries of juvenile shrimp carrying different SSCP genotypes were not significantly different (P < 0.05). Interestingly, expression of Pm-RuvBL2 in the ovaries of P. monodon juveniles was significantly up-regulated upon 5-HT administration (50 μg/g body weight, P < 0.05). The expression level of Pm-RuvBL2 in the ovaries of broodstock was greater than that of juvenile shrimp (P < 0.05). Results critically suggested that Pm-RuvBL2 should play an important role in growth and reproduction of P. monodon.