Submitted to: Animal Genetics International Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/3/2008
Publication Date: 7/20/2008
Citation: McDaneld, T.G., Wiedmann, R.T., Miles, J.R., Smith, T.P. 2008. MicroRNA profiles in skeletal muscle of fetal pig. XXXI Animal Genetics International Conference Proceedings. Poster #2206.
Technical Abstract: MicroRNA (miR) are a class of small RNAs that regulate gene expression by inhibiting translation of protein encoding transcripts through activation of a specific cellular pathway. Recently, miR have been reported to regulate multiple cellular processes of skeletal muscle development and growth including cell fate determination and differentiation. Fetal skeletal muscle growth is characterized by an increase in cell number and cell size, in which miR may play a role. To evaluate the role of miR in skeletal muscle growth of the fetal pig, global miR expression in biceps femoris and longissimus dorsi at three stages of growth, including: primary fiber development (d 60), secondary fiber development (d 90), and preparturition (d 105), were measured. Additionally, miR expression in the adult biceps femoris was evaluated to compare muscle that has reached mature stage of the growth curve (adult) to rapidly growing muscle (fetal). Longissimus dorsi and biceps femoris samples were isolated and pooled based on sex from 4 female and 4 male fetuses at 60, 90, and 105 days of gestation. Biceps femoris was also obtained from each adult sow. MicroRNA clone libraries were created to measure miR expression. A total of 95 miR matched sequences in the database with three sequences representing novel miR. Muscle-specific miR-206 was the highest expressed miR at all time points evaluated in longissimus dorsi and biceps femoris. Additionally, muscle-specific miR-1 was moderately expressed throughout fetal development with highest expression at later stages of development, while miR-133 was either not detectable or lowly expressed throughout fetal development. Similar to miR-1, other miR including let-7 and miR-199 were moderately expressed throughout development, while miR-106, miR-181, miR-20, miR-800, and miR-93 were lowly expressed. Changes in miR expression specific to stages of fetal development were also observed. MiR-432 was moderately expressed during early fetal development at d 60 compared to d 90 and d 105. Additionally, miR-424 expression increased during d 90, and miR-126 increased during d 105. These data are the first to evaluate miR expression at specific stages of fetal skeletal muscle growth in swine and identify miR that may play a vital role in skeletal muscle development and growth.