Differential expression of select members of the SLC family of genes and regulation of expression by microRNAs in the chicken oviduct

The yolk and white of eggs from chickens contain proteins and other molecules either secreted or transported by cells of the reproductive tract, or secreted by the liver and transported to the ovarian follicles of laying hens. Nutrients transported by solute carriers (SLCs) include glucose, electrolytes, and amino acids. Although SLC genes have been investigated in mammals, there are few studies of expression of SLC genes in the chicken oviduct. Therefore, we investigated temporal and cell-specific expression of selected SLC genes at 3 h and 20 h postovulation and regulation of their expression by microRNAs (miRs). Expression of SLC1A4 (glutamate and neutral amino acid transporter), SLC13A2 (dicarboxylate transporter), and SLC35B4 (UDP-xylose: UDP-N-acetylglucosamine transporter) mRNAs was limited to glandular epithelium (GE), while SLC4A5 (sodium bicarbonate cotransporter) and SLC7A3 (cationic amino acid transporter) mRNAs were expressed predominantly in the luminal epithelium of the magnum. Interestingly, SLC1A4, SLC4A5, SLC13A2 and SLC35B4 mRNAs were abundant only in GE of the shell gland, whereas SLC7A3 was not detected in the shell gland. In the magnum, SLC7A3 and SLC4A5 were expressed, but SLC1A4, SLC35B4, and SLC13A2 were not expressed at 20 h postovulation. In the shell gland, all SLC mRNAs were expressed at both time points, except for SLC7A3. The miRNA target validation assay revealed that miR-1764 and miR-1700 bind directly to SLC13A2 and SLC35B4 transcripts, respectively, to regulate expression. Results of this study demonstrate cell-specific and temporal changes in expression of selected SLC genes and regulation of SLC13A2 and SLC35B4 expression by miRs in the oviduct of laying hens.