Molecular characterization and nutritional regulation of sodium-dependent glucose cotransporter 1 (Sglt1) in blunt snout bream (Megalobrama amblycephala)

Abstract

Fish has poor utilization capacity for glucose metabolism. The possible reasons are related to the core regulatory elements of glucose metabolism: transport proteins. Studies on the species and functions of Sglt1 in aquatic animals are scarce, therefore further studies are needed. In this study, the full length of blunt snout bream (Megalobrama amblycephala) sglt1 (Masglt1) was 2965 bp including 5′-UTR region of 168 bp and a 3′-UTR region of 820 bp. Masglt1 have a highest sequence homology in Cypriniformes fish. MaSglt1 protein was identified as a transmembrane protein with 14 α-helix structures locating plasma membrane by the methods of predicted tertiary structure and immunohistochemical staining. MaSglt1 protein has a hollow channel forms which could be specifically coupled with two Na+ ions to recognize glucose and carry out transmembrane transport. High sglt1 mRNA was found in the intestine and kidney. The mRNA levels of intestinal sglt1 had a positive correlation with dietary starch levels at 3 h after feeding, and the mRNA was significantly higher than that at 24 h, however, the mRNA levels of renal sglt1 presented results opposite to those of intestinal sglt1. The mRNA levels of renal sglt1 had a positive correlation with dietary starch levels at 24 h after feeding, and the expression was significantly higher than that at 3 h. These results confirmed that Masglt11 was mainly found in the intestine and kidney and was located in the cell membrane, playing a role in glucose homeostasis.

Comparative Study of Sodium-Dependent Glucose Co-Transporters in Kidneys of Ostrich Chickens

“…The sodium-dependent glucose co-transporter 1 (SGLT1) and sodium-dependent glucose co-transporter 2 (SGLT2) are the members of the solute carrier 5 (SLC 5A) gene family (Mota et al, 2015;Wright, 2021). SGLT1, encoded by the SLC 5A1 gene (Liang et al, 2021), has been reported as the high affinity Na+-glucose co-transporter, while SGLT2 encoded by the SLC 5A2 gene -as the low affinity Na+-glucose co-transporter (Kanai et al, 1994). In humans, SLC 5A1 gene encodes the production of the SGLT1 protein to line the epithelial cells of the kidney tubules of the nephron for glucose uptake into cells (Lodish et al, 2016).…”