Specificity Protein 1 Regulates Gene Expression Related to Fatty Acid Metabolism in Goat Mammary Epithelial Cells

Abstract

Specificity protein 1 (SP1) is a ubiquitous transcription factor that plays an important role in controlling gene expression. Although important in mediating the function of various hormones, the role of SP1 in regulating milk fat formation remains unknown. To investigate the sequence and expression information, as well as its role in modulating lipid metabolism, we cloned SP1 gene from mammary gland of Xinong Saanen dairy goat. The full-length cDNA of the SP1 gene is 4376 bp including 103 bp of 5'UTR, 2358 bp of ORF (HM_236311) and 1915 bp of 3'UTR, which is predicted to encode a 786 amino acids polypeptide. Phylogenetic tree analysis showed that goat SP1 has the closest relationship with sheep, followed by bovines (bos taurus, odobenus and ceratotherium), pig, primates (pongo, gorilla, macaca and papio) and murine (rattus and mus), while the furthest relationship was with canis and otolemur. Expression was predominant in the lungs, small intestine, muscle, spleen, mammary gland and subcutaneous fat. There were no significant expression level differences between the mammary gland tissues collected at lactation and dry-off period. Overexpression of SP1 in goat mammary epithelial cells (GMECs) led to higher mRNA expression level of peroxisome proliferator-activated receptor-γ (PPARγ) and lower liver X receptor α (LXRα) mRNA level, both of which were crucial in regulating fatty acid metabolism, and correspondingly altered the expression of their downstream genes in GMECs. These results were further enhanced by the silencing of SP1. These findings suggest that SP1 may play an important role in fatty acid metabolism.

Biosynthesis of milk fat, protein, and lactose: roles of transcriptional and posttranscriptional regulation

“…The important role of PPAR␥ in the mouse indicated by the in silico analysis is not supported by experimental data, as discussed above. At least one TFBS for the Sp1 was present in all milk fat-related genes, supporting a role for this TF, as recently demonstrated (257).…”

“…Very recently it was demonstrated that the Specificity protein 1 (Sp1) also plays a role in controlling milk fat synthesis in goat mammary cells (257). The overexpression of Sp1 increased the transcription of several genes involved in milk fat synthesis, including PPARG, whereas the SREBF1 remained unaffected and the NR1H2 was downregulated (257).…”

miR-148a and miR-17–5p synergistically regulate milk TAG synthesis via PPARGC1A and PPARA in goat mammary epithelial cells

“…10,47,66 With increaesd miRNA research, researchers are trying to combine the data from different approaches (genomics, proteomics, and miRNA genomics) to obtain more effective data for practical application. 57,60 Although there are many methods used to analyze mRNA and miRNA for lipid metabolism 55 , there has been no miRNA-mRNA regulation analysis performed in milk goats.…”

“…66 In brief, GMEC were transfected with miR-148a, miR-17-5p mimic or inhibitor, were cleaned several times in PBS (phosphate buffer solution), and were fixed in 10% paraformaldehyde for 30 minutes. Afterwards, cells were stained using 10% oil red O in isopropanol for 10 minutes, were cleaned by PBS, and were detected microscopically.…”

miR-30e-5p and miR-15a Synergistically Regulate Fatty Acid Metabolism in Goat Mammary Epithelial Cells via LRP6 and YAP1

“…Previous research illustrated that miRNA plays an important role in mammary development and lactation [35,36,37]. For instance, Avril-Sassen et al screened and compared the expression of 102 miRNA in different stages of lactation in mice and speculated that some differentially-expressed miRNA were related to fatty acid metabolism [38].…”