Lindholm-Perry A K, Kuehn L A, Oliver W T, Kern R J, Cushman R A, Miles J R, McNeel A K, Freetly H C
USDA, ARS, U.S. Meat Animal Research Center, PO Box 166, Clay Center, NE, 68933, USA.
Anim Genet. 2014 Aug;45(4):461-72. doi: 10.1111/age.12151. Epub 2014 Apr 15.
Beef steers with variation in feed efficiency phenotypes were evaluated previously on a high-density SNP panel. Ten markers from rs110125325-rs41652818 on bovine chromosome 4 were associated with average daily gain (ADG). To identify the gene(s) in this 1.2-Mb region responsible for variation in ADG, genotyping with 157 additional markers was performed. Several markers (n = 41) were nominally associated with ADG, and three of these, including the only marker to withstand Bonferroni correction, were located within the protein kinase, AMP-activated, gamma 2 non-catalytic subunit (PRKAG2) gene. An additional population of cross-bred steers (n = 406) was genotyped for validation. One marker located within the PRKAG2 loci approached a significant association with gain. To evaluate PRKAG2 for differences in transcript abundance, we measured expression in the liver, muscle, rumen and intestine from steers (n = 32) with extreme feed efficiency phenotypes collected over two seasons. No differences in PRKAG2 transcript abundance were detected in small intestine, liver or muscle. Correlation between gene expression level of PRKAG2 in rumen and average daily feed intake (ADFI) was detected in both seasons (P < 0.05); however, the direction differed by season. Lastly, we evaluated AMP-activated protein kinase (AMPK), of which PRKAG2 is a subunit, for differences among ADG and ADFI and found that the phosphorylated form of AMPK was associated with ADFI in the rumen. These data suggest that PRKAG2 and its mature protein, AMPK, are involved in feed efficiency traits in beef steers. This is the first evidence to suggest that rumen AMPK may be contributing to ADFI in cattle.
先前在高密度SNP基因芯片上对具有不同饲料效率表型的肉牛进行了评估。牛4号染色体上rs110125325 - rs41652818的10个标记与平均日增重（ADG）相关。为了确定该1.2兆碱基区域中负责ADG变异的基因，使用另外157个标记进行了基因分型。有几个标记（n = 41）名义上与ADG相关，其中三个，包括唯一经Bonferroni校正仍显著的标记，位于蛋白激酶AMP激活的γ2非催化亚基（PRKAG2）基因内。另外一组杂交肉牛（n = 406）进行了基因分型以作验证。位于PRKAG2基因座内的一个标记接近与增重显著相关。为了评估PRKAG2转录本丰度的差异，我们测量了在两个季节收集的具有极端饲料效率表型的肉牛（n = 32）的肝脏、肌肉、瘤胃和肠道中的表达。在小肠、肝脏或肌肉中未检测到PRKAG2转录本丰度的差异。在两个季节中均检测到瘤胃中PRKAG2基因表达水平与平均日采食量（ADFI）之间的相关性（P < 0.05）；然而，相关性方向因季节而异。最后，我们评估了PRKAG2作为其亚基的AMP激活蛋白激酶（AMPK）在ADG和ADFI之间的差异，发现AMPK的磷酸化形式与瘤胃中的ADFI相关。这些数据表明PRKAG2及其成熟蛋白AMPK参与了肉牛的饲料效率性状。这是表明瘤胃AMPK可能影响牛ADFI的首个证据。
