The ontogeny of delta-like protein 1 messenger ribonucleic acid expression during muscle development and regeneration: Comparison of broiler and Leghorn chickens

Abstract

Delta-like protein 1 (DLK1) has been implicated in the muscle hypertrophy observed in DLK1 transgenic mice, callipyge sheep, and mouse paternal uniparental disomy 12 and human paternal uniparental disomy 14 syndromes. The current study was aimed to determine chicken DLK1 (gDLK1) mRNA expression during primary muscle cell differentiation and during muscle regeneration after cold injury and to compare gDLK1 mRNA expression during skeletal muscle development in layers and broilers. In chicken primary muscle cell culture, gDLK1 mRNA expression was significantly increased from 12 to 48 h (P < or = 0.05) when the nascent myotubes were actively formed at d 2 to 3. Myogenin, a late myogenic marker gene, mRNA expression peaked at 36 to 48 h. Myogenic differentiation 1 (MyoD) and paired box gene 7 (Pax7), early myogenic marker genes, mRNA expression gradually decreased during myogenic differentiation. During muscle regeneration, the expression of MyoD and Pax7 peaked at d 2 (P < or = 0.05), and myogenin mRNA expression peaked at d 4 (P < or = 0.05). The induction of gDLK1 gene appeared between d 7 to 10 postinjury (P < or = 0.05) when myotubes were actively formed as also demonstrated in histological sections. The expression of gDLK1 was slowly downregulated to the control levels at d 14 when the damaged muscle appeared nearly healed. These data suggest that gDLK1 may be involved in the late myogenic stages of primary muscle cell differentiation and muscle regeneration. The gDLK1 mRNA in the muscle tissues was very abundant at embryonic ages but decreased after hatching in both broiler and layer chickens. Compared with layers, broiler muscle at embryonic d 13 had a 3-fold greater expression of DLK1 (P < or = 0.01). In addition, the gDLK1 mRNA expression at d 1, 11, and 33 post-hatch was significantly higher in broilers than layers (P < or = 0.05). Therefore, the relatively greater expression of the gDLK1 gene in muscles of broilers compared with layers suggests that gDLK1 may serve as a new selection marker for high muscle growth in chickens. These findings may provide new insight into chicken muscle development and regeneration.

Technical note: A gene delivery system in the embryonic cells of avian species using a human adenoviral vector

“…Embryonic pectoralis major muscle tissues of the chicken and quail were dissected from 11-and 10-d-old embryos, respectively. The isolation and culture of primary cells from pectoralis major muscles was performed as described previously (Shin et al, 2009). All primary avian cells were cultured 3 to 4 d for the studies of Ad5 transduction and dual expression of Ad5 containing a target gene or cultured 15 d for a duration study of Ad5 transduction.…”

“…Cell fixation, washing, and immunostaining of primary and secondary antibodies were followed as described previously (Li et al, 2009;Shin et al, 2009). The primary antibodies were a pan sarcomeric myosin heavy chain [MyHC (NA4), 1:500; The Developmental Studies Hybridoma Bank, Iowa City, IA] and the anti-HIBCH rabbit serum (1:500, a generous gift from John W. Hawes at Miami University, Oxford, OH).…”

Epigenetics and developmental programming of welfare and production traits in farm animals

“…These sheep have a complex genotype with a mutation in an imprinted regulatory region that leads to increased expression of DLK1, part of the Notch/Delta signalling pathway. Overexpression of DLK1 in skeletal muscle increases muscle mass (Davis et al 2004) and DLK1 is also upregulated in broiler chickens (Shin et al 2009), suggesting that it may be a good target for intervention in various species. It appears that the callipyge phenotype relates primarily to changes in postnatal rather than prenatal muscle growth, but it does have a complex inheritance pattern (see Georges et al 2003).…”

Expression of DLK1 and MEG3 genes in porcine tissues during postnatal development

“…These results have been confirmed through QTL (Quantitative Trait Locus) analysis, although the molecular mechanism involved has, as yet, not been stated (Li et al , 2008). Recently, gDLK1 has been proposed as a novel selection-marker for high muscle growth in chickens, since observed DLK1 mRNA expression was greater in the muscles of broilers than in layers (Shin et al , 2009). …”