Zhan K, Hou Z C, Li H F, Xu G Y, Zhao R, Yang N
Department of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100094.
Poult Sci. 2006 Oct;85(10):1746-54. doi: 10.1093/ps/85.10.1746.
Thyroid hormone responsive Spot 14 (THRSP) is suggested as a transcription factor involved in the regulation of adipogenic enzymes by 3 thyroid response elements in the promoter region. In the chicken genome, THRSP gene was identified to duplicate into 2 paralogs, THRSPalpha and THRSPbeta. In the current study, cDNA sequences of the duplicated duck THRSP genes were cloned by real-time PCR and rapid amplification of cDNA ends. Duck THRSPalpha and THRSPbeta were predicted to encode peptides with 133 amino acids, which had 74 and 68% sequence identity at cDNA level, 78 and 74% identity at amino acid level to the chicken counterparts, respectively. A high percentage (73.1%) of G and C nucleotides were found in the 3' untranslated region of duck THRSPbeta cDNA. Although a low similarity of peptide composition was shared between ducks and mammals, and a moderate similarity was shared between ducks and chickens, many predicted properties of THRSP, including the pI, subcellular localization and functional domains seemed to be highly conserved. The present study demonstrated that the duck THRSP gene duplicates into the 2 paralogs as in chickens. Phylogenetic analysis indicated that the duplication for THRSP paralogs appeared to have taken place preceding the chicken-duck split, and the diverging rate between THRSP paralogs seemed faster in the chicken genome than that in the duck genome. Expression analysis by real-time quantitative PCR showed that THRSP paralogs in ducks were more actively transcribed in fat tissues (i.e., s.c. fat and abdominal fat) than in liver, and the mRNA concentrations of THRSPbeta were higher than that of THRSPalpha in liver and s.c. fat.
甲状腺激素反应性Spot 14（THRSP）被认为是一种转录因子，通过启动子区域的3个甲状腺反应元件参与脂肪生成酶的调控。在鸡基因组中，THRSP基因被鉴定为复制成2个旁系同源基因，即THRSPα和THRSPβ。在本研究中，通过实时PCR和cDNA末端快速扩增克隆了复制的鸭THRSP基因的cDNA序列。鸭THRSPα和THRSPβ预计编码含133个氨基酸的肽，它们在cDNA水平上的序列同一性分别为74%和68%，在氨基酸水平上与鸡的对应物分别具有78%和74%的同一性。在鸭THRSPβ cDNA的3'非翻译区发现了高比例（73.1%）的G和C核苷酸。尽管鸭与哺乳动物之间肽组成的相似性较低，与鸡之间的相似性适中，但THRSP的许多预测特性，包括pI、亚细胞定位和功能域似乎高度保守。本研究表明，鸭THRSP基因如鸡一样复制成2个旁系同源基因。系统发育分析表明，THRSP旁系同源基因的复制似乎发生在鸡和鸭分化之前，并且THRSP旁系同源基因在鸡基因组中的分化速率似乎比鸭基因组中的更快。通过实时定量PCR进行的表达分析表明，鸭的THRSP旁系同源基因在脂肪组织（即皮下脂肪和腹部脂肪）中的转录比在肝脏中更活跃，并且在肝脏和皮下脂肪中THRSPβ的mRNA浓度高于THRSPα。
