Differential expression of the <i>GTL2</i> gene within the callipyge region of ovine chromosome 18

Bidwell, Christopher A.; Shay, T. L.; Georges, Michel; Beever, J. E.; Berghmans, Stéphane; Cockett, Noelle E.

doi:10.1046/j.1365-2052.2001.00776.x

Cited by 27 publications

(24 citation statements)

References 38 publications

(44 reference statements)

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“…Our results for MEG3 agree with those previously reported by Charlier et al (2001a) and Bidwell et al (2001) in that there is an increase in maternally expressed MEG3 from alleles carrying the mutation. In the Charlier et al study, MEG3 transcripts were elevated in longissimus dorsi of unaf- PAT sheep, these results together suggest that MEG3 is unlikely to be a direct mediator of the muscle hypertrophy phenotype.…”

Section: Discussionsupporting

confidence: 81%

Abnormal postnatal maintenance of elevated DLK1 transcript levels in callipyge sheep

et al. 2005

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The underlying mechanism of the callipyge muscular hypertrophy phenotype in sheep (Ovis aries) is not presently understood. This phenotype, characterized by increased glycolytic type II muscle proportion and cell size accompanied by decreased adiposity, is not visibly detectable until approximately three to eight weeks after birth. The muscular hypertrophy results from a single nucleotide change located at the telomeric end of ovine Chromosome 18, in the region between the imprinted MATERNALLY EXPRESSED GENE 3 (MEG3) and DELTA, DROSOPHILA, HOMOLOG-LIKE 1 (DLK1) genes. The callipyge phenotype is evident only when the mutation is paternally inherited by a heterozygous individual. We have examined the pre-and postnatal expression of MEG3 and DLK1 in sheep of all four possible genotypes in affected and unaffected muscles as well as in liver. Here we show that the callipyge phenotype correlates with abnormally high DLK1 expression during the postnatal period in the affected sheep and that this elevation is specific to the hypertrophy-responsive fast-twitch muscles. These results are the first to show anomalous gene expression that coincides with both the temporal and spatial distribution of the callipyge phenotype. They suggest that the effect of the callipyge mutation is to interfere with the normal postnatal downregulation of DLK1 expression.

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Section: Discussionsupporting

confidence: 81%

Abnormal postnatal maintenance of elevated DLK1 transcript levels in callipyge sheep

et al. 2005

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“…However, a potential function for SNP CLPG has been inferred from studies that examined the expression patterns of genes in the DLK1-GTL2 cluster in animals of the four CLPG genotypes. Northern blot analysis of longissimus muscle-derived RNA has demonstrated that the expression of DLK1, GTL2, PEG11, antiPEG11, and MEG8 is altered in a genotype-and muscle-specific manner [5,13]. Specifically, the expression levels of these genes are increased in longissimus muscle from 8-week-old individuals when the CLPG mutation is inherited in cis, yet these genes maintain their exclusive expression from either the paternal or maternal allele [13].…”

Section: The Callipyge (Clpg) Locusmentioning

confidence: 99%

The callipyge mutation and other genes that affect muscle hypertrophy in sheep

et al. 2005

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-Genetic strategies to improve the profitability of sheep operations have generally focused on traits for reproduction. However, natural mutations exist in sheep that affect muscle growth and development, and the exploitation of these mutations in breeding strategies has the potential to significantly improve lamb-meat quality. The best-documented mutation for muscle development in sheep is callipyge (CLPG), which causes a postnatal muscle hypertrophy that is localized to the pelvic limbs and loin. Enhanced skeletal muscle growth is also observed in animals with the Carwell (or rib-eye muscling) mutation, and a double-muscling phenotype has been documented for animals of the Texel sheep breed. However, the actual mutations responsible for these muscular hypertrophy phenotypes in sheep have yet to be identified, and further characterization of the genetic basis for these phenotypes will provide insight into the biological control of muscle growth and body composition.sheep / muscle / hypertrophy / callipyge / mutation

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“…The expression patterns of a number of the imprinted genes surrounding the callipyge mutation are dysregulated in affected skeletal muscles (6,7,13,48,69). These genes include Dlk1, Gtl2, Peg11, Peg11as, and Meg8.…”

mentioning

confidence: 98%

Identification of a gene network contributing to hypertrophy in callipyge skeletal muscle

Vuocolo

Byrne

White

et al. 2007

Physiological Genomics

106

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The callipyge mutation in sheep results in postnatal skeletal muscle hypertrophy in the pelvic limbs and loins with little or no effect on anterior skeletal muscles. Associated with the phenotype are changes in the expression of a number of imprinted genes flanking the site of the mutation, which lies in an intergenic region at the telomeric end of ovine chromosome 18. The manner in which these local changes in gene expression are translated into muscle hypertrophy is not known. Microarray-based transcriptional profiling was used to identify differentially expressed genes in longissimus dorsi skeletal muscle samples taken at birth and 12 wk of age from callipyge and wild-type sheep. The phenotype was only expressed at the latter developmental time and associated with decreased type 1 fibers (slow oxidative) and a shift toward type IIx and IIb fibers (fast-twitch glycolytic). We have identified 131 genes in the samples taken at 12 wk of age that were differentially expressed as a function of genotype but not due to the fiber type changes. The gene expression changes occurring as a function of genotype in the samples taken at birth indicated that the transcriptional framework underpinning the phenotype was emerging prior to expression of the phenotype. Eight genes were differentially expressed as a function of genotype at both developmental times. A model is proposed describing a core network of genes and histone epigenetic modifications that is likely to underpin the fiber type changes and muscle hypertrophy characteristic of callipyge sheep.

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Differential expression of the GTL2 gene within the callipyge region of ovine chromosome 18

Cited by 27 publications

References 38 publications

Abnormal postnatal maintenance of elevated DLK1 transcript levels in callipyge sheep

Abnormal postnatal maintenance of elevated DLK1 transcript levels in callipyge sheep

The callipyge mutation and other genes that affect muscle hypertrophy in sheep

Identification of a gene network contributing to hypertrophy in callipyge skeletal muscle

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