Identification of a novel antisense RNA that regulates growth hormone receptor expression in chickens

Natural antisense transcripts (NATs) are widely present in mammalian genomes and act as pivotal regulator molecules of gene expression. However, studies on NATs in the chicken are relatively rare. We identified a novel antisense transcript in the chicken, designated <i>GHR-AS-EST</i>, transcribed from the growth hormone receptor (<i>GHR</i>) locus, which encodes a well-known regulatory molecule of muscle development and fat deposition. <i>GHR-AS-EST</i> is predominantly expressed in the chicken liver and muscle tissues. <i>GHR-AS-EST</i> sequence conservation among vertebrates is weak. <i>GHR-AS-EST</i> forms an RNA–RNA duplex with <i>GHBP</i> to increase its stability, and regulates the expression of <i>GHR</i> sense transcripts at both the mRNA and protein levels. Further, <i>GHR-AS-EST</i> promotes cell proliferation by stimulating the expression of signaling factors in the JAK2/STAT pathway, and contributes to fat deposition via downregulating the expression of signaling factors in the JAK2/SOCS pathway in LMH hepatocellular carcinoma cells. We expect that the discovery of a NAT for a regulatory gene associated with cell proliferation and lipolysis will further our understanding of the molecular regulation of both muscle development and fat deposition.