Abstract. Intramuscular fat deposition in the longissimus dorsi
muscle (LM) of Korean cattle steer is regulated by several genes related to
lipid metabolism. One of these genes encodes the enzyme bovine
glycerol-3-phosphate acyltransferase, mitochondrial (GPAM), which is located on
the mitochondrial outer membrane and catalyzes the initial and committed
step of glycerolipid synthesis in lipid metabolism of cattle. Previous
studies have shown that the 3′-untranslated region (UTR) of the
GPAM is quite extended and contains a polyadenylation signal site, erythroid
15-lipoxygenase differentiation control elements (15-LOX-DICEs), and
cytoplasmic polyadenylation elements (CPEs) that affect the regulation of
triacylglycerol synthesis. Therefore, the aim of this study was to
identify single-nucleotide polymorphisms (SNPs) related to the regulation of
glycerolipid synthesis in the 3′-UTR of GPAM and to verify the function
of SNPs affecting the deposition of intramuscular fat in Korean cattle
steer. In the present study, 11 SNPs were discovered in the 3′-UTR
of GPAM. Among these SNPs, g.54853A>G, g.55441A>G, and
g.55930C>T were significantly associated with marbling score in
a Korean cattle steer population and were strongly correlated with each other
within the GPAM gene. Furthermore, based on the results predicted by the
RNAhybrid program, four putative microRNAs (miRNAs) were identified, and the
above SNPs were found to present in the seed region of these miRNAs. These
miRNAs have a differential binding affinity for each allele of SNPs
g.54853A>G, g.55441A>G, and g.55930C>T.
The in vivo evidence of intramuscular fat deposition in the LM tissue showed that
these SNPs affected the regulation of intramuscular fat deposition in Korean
cattle steer. Thus, the g.54853A>G, g.55441A>G, and
g.55930C>T could be considered as causal mutations regulating
intramuscular fat deposition in Korean cattle steer.
Expression of lipid metabolism genes provides new insights into intramuscular fat deposition in Laiwu pigs