Identification of differentially expressed genes between high and low marbling score grades of the longissimus lumborum muscle in Hanwoo (Korean cattle).

We conducted DD-RT-PCR analysis to identify differentially expressed genes between high and low marbling score groups with extremely different IMF content of the longissimus lumborum muscles in Hanwoo. We detected 137 DEGs between two marbling score groups. Of these DEGs, 41 DEGs were highly expressed in the high marbling score group, whereas 96 DEGs showed a higher expression in the low marbling score group. Among them, we selected eight DEGs exhibiting the greatest differential expression levels between two marbling score groups. These genes could be classified as five candidate genes according to homology to known genes and biological functions. The expression of four DEGs except for ATP6 gene was confirmed by qRT-PCR. The TPI1 gene was significantly higher expressed at the high marbling group, whereas ACTA1, TNNT1 and MDH2 genes were significantly higher expressed at the low marbling group. Therefore, the TPI1 gene was up-regulated, suggesting that this gene may have an important function related to IMF deposition.