Abstract:
To elucidate the role of intestinal fatty acid binding protein (Ifabp) in the regulation of lipids metabolism, unigenes were obtained from transcriptome of liver in spotted scat,
Scatophagus argus. Two subtypes of
ifabp genes (
ssifabp2
a and
ssifabp2
b) were isolated and analyzed in the female and male
S. argus, respectively. Tissue distributions and changes of
ssifabp2
a and
ssifabp2
b in fast feeding and re-feeding were also observed. Phylogenetic tree results showed that ssIfabp2a was clustered with other Ifabp2a, Ifabp or IfabpX1, while ssIifabp2b was clustered with Ifabp2b or Ifabp-like in Osteichthyes. Homology analysis revealed that the sequence identity of ssifabp2a was 78.8%—87.9% with other Osteichthyes Ifabp2a, Ifabp or IfabpX1. The sequence identity of ssifabp2b was 79.5%—87.9% with other Osteichthyes Ifabp2b or Ifabp-like. The sequence identity was 73.5% between ssifabp2a and ssifabp2b. RT-PCR showed that
ssifabp2
a was the highest in intestine, and had a moderate level in kidney and liver. And
ssifabp2
b was also the highest in intestine, but had a moderate level in liver, stomach and hypothalamus in male. However, the expression of
ssifabp2
a was the highest in stomach, and moderate in kidney, liver and hypothalamus, with a weak expression level in other tissues and no expression in pituitary. The
ssifabp2
b was expressed strongly in hypothalamus, ovary, heart and intestine, and weakly in other tissues, but had no expression in gill of females. In the intestine, the expression of
ssifabp2
a decreased significantly, but there was no significant change of
ssifabp2
b after 2d of food deprivation. The expression of
ssifabp2
a decreased significantly compared with the control group, but there was no significant difference on the expression of
ssifabp2
b within the 7 day fasting group. The expressions of
ssifabp2
a and
ssifabp2
b increased significantly with refeeding 3-h after the scheduled feeding time. In liver, the expression of
ssifabp2
a was not changed, but the expression of
ssifabp2
b increased significantly after 2-day of food deprivation. However, the
ssifabp2
a and
ssifabp2
b were all increased during the 7-day fasting, and decreased significantly with refeeding 3-h after the scheduled feeding time. In summary, ssIfabp2a and ssIfabp2b are involved in the regulation of lipids metabolism at liver and intestine in
Scatophagus argus.