|Cushman, Robert - Bob|
Submitted to: International Society for Animal Genetics (ISAG)
Publication Type: Abstract Only
Publication Acceptance Date: 3/16/2017
Publication Date: N/A
Citation: N/A Interpretive Summary:
Technical Abstract: Prenatal myogenesis is a critical factor in determining the muscle growth potential of cattle. We hypothesized that maternal nutrient restriction during early gestation would alter the transcriptome of fetal primordial muscle tissue in cattle. A total of 14 Angus-cross heifers were estrus synchronized and assigned at breeding to one of two dietary treatments (CON- 100% of nutrient requirements; RES- 60% of CON). At d 50 of gestation heifers were ovariohysterectomized, and fetal muscle tissue from the hind limb was dissected and flash frozen. RNA was extracted and RNA-seq analysis was conducted on the Illumina HiSeq 2500 platform using 50-bp paired-end reads at a depth of 2 × 10.4M reads/sample. Transcriptome analysis was performed in collaboration with USDA-ARS-MARC using the Tuxedo Suite, and KEGG pathways were analyzed with DAVID 6.8. A total of 317 genes (P < 0.01) were used for pathway analysis, of which 92 were false discovery rate protected (q < 0.10). Within the fetal muscle KEGG cluster, 22 genes were identified as differentially expressed with all but three of being upregulated in RES. These include the myogenic genes MYOG and MYOD1 (1.49 and 1.39 fold greater than CON, respectively), both of which play important roles in skeletal muscle cell differentiation and fiber development. Four members of the Wnt signaling pathway, namely WNT5A, FZD1, APC2, and FZD10, were upregulated in RES fetuses (1.32-2.11 fold greater than CON). The Wnt pathway is critical in promoting the differentiation of myocytes from progenitor stem cells. Additional genes upregulated in RES include members of the troponin (TNNC1, TNNC2, TNNI1, TNNI2, TNNT1, TNNT2, TPM2), myosin (MYL1, MLY2, MLY4, MLY7, MYL6B, MLY9, MYH8, MYLPF), and actin (ACTA1, ACTA2, ACTG2) families. These data support our hypothesis that moderate maternal nutrient restriction within the first 50 d of gestation alters the fetal muscle transcriptome, specifically up-regulating myogenic genes in RES fetuses. Therefore we conclude that early gestation is an important period of myogenic developmental programming in cattle.