Transcriptome analysis of two bovine muscles during ontogenesis

Area of Science:

• Animal Genetics
• Developmental Biology
• Molecular Biology

Background:

• Understanding gene expression patterns in bovine muscle development is crucial for livestock improvement.
• Ontogenesis involves complex molecular changes that dictate muscle fiber type and function.

Purpose of the Study:

• To create a bovine muscle gene repertoire using macro-arrays.
• To identify differentially expressed genes in bovine skeletal muscle during ontogenesis.
• To investigate the role of specific genes in muscle development, particularly during late gestation.

Main Methods:

• Utilized macro-arrays with 1339 human skeletal muscle cDNA clones for gene expression profiling.
• Analyzed gene expression in Rectus abdominis (oxidative) and Semitendinosus (glycolytic) muscles from fetal stages (110-260 days) and young bulls (15 months).
• Employed a heterologous approach with pooled RNA samples from multiple animals for robust analysis.

Main Results:

• Identified up to 7 genes differentially expressed between oxidative and glycolytic muscles, varying with age.
• Detected expression level differences in 110 genes across developmental stages from 110 days gestation to 15 months.
• Observed significant gene overexpression (87 genes) and down-regulation (7 genes) when comparing late-fetal to adult muscle, with 33% of these genes having unknown functions.

Conclusions:

• The last trimester of gestation is a critical period for bovine muscle myogenesis.
• This study provides a foundational bovine muscle gene repertoire and identifies novel genes involved in muscle development.
• Findings offer insights into the genetic regulation of muscle development and potential targets for livestock breeding programs.