Molecular and functional characterization of sirt4 and sirt6 in Megalobrama amblycephala under high glucose metabolism.

We analyzed the sequences of sirt4 and sirt6 and their changes in expression after oral glucose administration in blunt snout bream (Megalobrama amblycephala). We cloned sirt4 and sirt6 and found that their full-length cDNA sequences were 1530 bp and 1723 bp, respectively; their amino acid sequences were 93% and 92% identical to Danio rerio. Megalobrama amblycephala were fed a high glucose solution (3 g/kg). Normally, sirt4 expression is higher in spleen, intestine, and gill (P < .05), and sirt6 expression is higher in intestine and gill (P < .05). After oral glucose administration, sirt4 and sirt6 expression increased in liver and gill, and sirt4 expression increased in intestine at 0.5 h (P < .05). In contrast, sirt4 in kidney and sirt6 in head kidney were downregulated at 1 h (P < .05). Expression of sirt4 was upregulated in brain, head kidney, spleen, muscle, and liver 2 h, 4 h, 4 h/24 h, 8 h, and 24 h, respectively (P < .05). Expression of sirt4 was downregulated in kidney at 8 h-48 h (P < .05). Expression of sirt6 was upregulated in intestine, liver, muscle, kidney, and spleen at 4 h/24 h, 8 h/24 h, 12 h, 12 h, and 24 h, respectively (P < .05). We report that sirt4 and sirt6 are highly conserved in evolution and exhibit tissue-specific expression profiles. We demonstrate that the expression of sirt4 and sirt6 are tissue-specific, and depend upon tissue-specific responses to glucose metabolism.