Author
Lindholm-Perry, Amanda | |
Kern, Rebecca | |
Kuehn, Larry | |
Snelling, Warren | |
Miles, Jeremy | |
Oliver, William | |
Freetly, Harvey |
Submitted to: Gene
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/28/2015 Publication Date: 9/24/2015 Publication URL: http://handle.nal.usda.gov/10113/61596 Citation: Lindholm-Perry, A.K., Kern, R.J., Kuehn, L.A., Snelling, W.M., Miles, J.R., Oliver, W.T., Freetly, H.C. 2015. Differences in transcript abundance of genes on BTA15 located within a region associated with gain in beef steers. Gene. 572(1):42-48. doi:10.1016/j.gene.2015.06.076. Interpretive Summary: A region on the bovine chromosome 15 was identified in a previous study as a region that contributes to beef steer weight gain. This region is gene rich and seven genes were tested for differences in expression in a steer tissue library consisting of adipose, muscle, small intestine, liver, rumen and spleen from 14 animals with extreme differences in weight gain. The genes evaluated were two olfactory receptor-like genes (LOC525033and LOC618173), RRM1, STIM1, RHOG, PGAP2, and NUP98. The expression of RHOG in the rumen was positively correlated with average daily gain (ADG) and STIM1 in the rumen exhibited a trend towards significant correlation with ADG. The expression of one olfactory receptor (LOC618173) in the ileum was also positively correlated with ADG and PGAP2 and LOC525033 in the ileum displayed trends for correlation with ADG. To further evaluate the differential expression detected in the ileum and rumen of these animals, the transcript abundance of these genes were assessed in an additional group of 32 animals with extreme ADG and average daily feed intake (ADFI) phenotypes collected over two seasons. The olfactory receptor LOC525033 was not expressed in the ileum for the majority of these animals. Only RHOG showed a slight but non-significant trend towards greater expression in animals with greater gain. We have detected differences in the transcript abundance of genes located within a specific chromosomal region previously associated with gain in the rumen and ileum of animals selected for extreme ADG; however, we were unable to validate the expression of these genes in the larger group of cattle possibly due to the differences in phenotype or contemporary group. Technical Abstract: Six markers on the Illumina Bovine 50k BeadChip within a 229 Kb region on bovine chromosome 15 were associated (P=0.002) with average daily gain (ADG) in beef cattle. We chose to evaluate seven genes located within this region for variation in RNA transcript abundance in a library of tissue samples that included adipose, muscle, small intestine (duodenum, ileum and jejunum), liver, rumen and spleen collected from steers (n=14) with extreme ADG phenotypes. The genes evaluated were two olfactory receptor-like genes (LOC525033and LOC618173), RRM1, STIM1, RHOG, PGAP2, and NUP98. The rumen transcript abundance of RHOG was positively correlated with ADG (P=0.02) and STIM1 exhibited a trend towards significant correlation with ADG (P=0.08). The transcript abundance of one olfactory receptor (LOC618173) in the ileum was also positively correlated with ADG (P=0.02) and PGAP2 and LOC525033 in the ileum displayed trends for correlation with ADG (P=0.1). To further evaluate the differential expression detected in the ileum and rumen of these animals, the transcript abundance of STIM1 and RHOG in the rumen and of PGAP2 and the olfactory receptors in the ileum were assessed in an additional group of 32 animals with extreme ADG and ADFI phenotypes collected over two seasons. The olfactory receptor LOC525033 was not expressed in the ileum for the majority of these animals. Only RHOG showed a slight but non-significant trend towards greater expression in animals with greater gain. We have detected differences in the transcript abundance of genes within this region in the rumen and ileum of animals selected for extreme ADG; however, we were unable to validate the expression of these genes in the larger group of cattle possibly due to the differences in phenotype or contemporary group. |