Cloning of the growth hormone receptor and its muscle-specific mRNA expression in black Muscovy duck (<i>Cairina moschata</i>)

The cDNA sequence of the growth hormone receptor (GHR) from the black Muscovy duck was obtained and compared to the mRNA expression of growth hormone (GH) in the breast and leg muscles during 2–13 weeks of age using quantitative RT-PCR.The cDNA sequence of the Muscovy duck GHR gene is 1903 bp in length, with an 1830 bp coding region that encodes 609 amino acids. It exhibits &gt; 92.9% homology with the poultry GHR cDNA and amino acid sequences.Overall, GHR mRNA expression was the highest at 2 weeks and the lowest at 13 weeks of age, exhibiting different profiles in different muscles. In the breast muscles, the GHR mRNA level declined sharply at 2–4 weeks, maintained at a plateau at 4–10 weeks and decreased slightly at 10–13 weeks. In the leg muscles, a gradual and slow decrease was observed during the whole period of 2–13 weeks.Robust extra-pituitary GH mRNA expression was detected in the muscles and the expression profile was highly correlated with that of GHR mRNA, in contrast to the inverse correlation between the pituitary GH and tissue GHR levels shown previously.These data suggest that the locally synthesised GH in the muscles, rather than the pituitary GH, is more closely associated with GHR and may be more critical for the regulation of muscle growth and contribute to the tissue-specific effects of GH. The cDNA sequence of the growth hormone receptor (GHR) from the black Muscovy duck was obtained and compared to the mRNA expression of growth hormone (GH) in the breast and leg muscles during 2–13 weeks of age using quantitative RT-PCR. The cDNA sequence of the Muscovy duck GHR gene is 1903 bp in length, with an 1830 bp coding region that encodes 609 amino acids. It exhibits &gt; 92.9% homology with the poultry GHR cDNA and amino acid sequences. Overall, GHR mRNA expression was the highest at 2 weeks and the lowest at 13 weeks of age, exhibiting different profiles in different muscles. In the breast muscles, the GHR mRNA level declined sharply at 2–4 weeks, maintained at a plateau at 4–10 weeks and decreased slightly at 10–13 weeks. In the leg muscles, a gradual and slow decrease was observed during the whole period of 2–13 weeks. Robust extra-pituitary GH mRNA expression was detected in the muscles and the expression profile was highly correlated with that of GHR mRNA, in contrast to the inverse correlation between the pituitary GH and tissue GHR levels shown previously. These data suggest that the locally synthesised GH in the muscles, rather than the pituitary GH, is more closely associated with GHR and may be more critical for the regulation of muscle growth and contribute to the tissue-specific effects of GH.本研究获取了黑番鸭生长激素受体（growth hormone receptor, GHR）的互补DNA（complementary DNA, cDNA）序列，并采用定量逆转录聚合酶链式反应（quantitative RT-PCR）技术，对比分析了2~13周龄期间其胸肌与腿肌内生长激素（growth hormone, GH）的mRNA表达水平。番鸭GHR基因的cDNA序列全长为1903 bp，其中编码区长度为1830 bp，可编码609个氨基酸。该序列与禽类GHR的cDNA及氨基酸序列的同源性高于92.9%。整体而言，GHR的mRNA表达量在2周龄时达到最高，13周龄时最低，且在不同肌肉组织中呈现出各异的表达模式。在胸肌中，GHR mRNA水平在2~4周龄时急剧下降，4~10周龄时维持平台期，10~13周龄时略有降低。在腿肌中，2~13周龄的整个周期内均呈现出缓慢且渐进的下降趋势。研究在肌肉组织中检测到了显著的垂体外GH mRNA表达，且其表达模式与GHR mRNA的表达高度相关，这与此前报道的垂体GH与组织GHR水平呈负相关的结果截然相反。上述数据表明，肌肉组织中局部合成的GH而非垂体来源的GH，与GHR的关联更为紧密，其可能在肌肉生长调控中发挥更为关键的作用，并有助于GH产生组织特异性的生物学效应。本研究获取了黑番鸭生长激素受体（growth hormone receptor, GHR）的互补DNA（complementary DNA, cDNA）序列，并采用定量逆转录聚合酶链式反应（quantitative RT-PCR）技术，对比分析了2~13周龄期间其胸肌与腿肌内生长激素（growth hormone, GH）的mRNA表达水平。番鸭GHR基因的cDNA序列全长为1903 bp，其中编码区长度为1830 bp，可编码609个氨基酸。该序列与禽类GHR的cDNA及氨基酸序列的同源性高于92.9%。整体而言，GHR的mRNA表达量在2周龄时达到最高，13周龄时最低，且在不同肌肉组织中呈现出各异的表达模式。在胸肌中，GHR mRNA水平在2~4周龄时急剧下降，4~10周龄时维持平台期，10~13周龄时略有降低。在腿肌中，2~13周龄的整个周期内均呈现出缓慢且渐进的下降趋势。研究在肌肉组织中检测到了显著的垂体外GH mRNA表达，且其表达模式与GHR mRNA的表达高度相关，这与此前报道的垂体GH与组织GHR水平呈负相关的结果截然相反。上述数据表明，肌肉组织中局部合成的GH而非垂体来源的GH，与GHR的关联更为紧密，其可能在肌肉生长调控中发挥更为关键的作用，并有助于GH产生组织特异性的生物学效应。