Hu Qiaomu, Tian Haifeng, Meng Yan, Xiao Hanbing
Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Science, Wudayuan First Road 8, 430223 Wuhan, People's Republic of
J Genet. 2016 Sep;95(3):683-90. doi: 10.1007/s12041-016-0685-3.
Lhx9 is an LIM (named for the first three proteins in which the domain was found, Lin-11, Isl1 and Mec-3) homeodomain protein involved in development and differentiation of the gonad. In this study, we isolated the full-length Lhx9 and Lhx9α from Andrias davidianus, detected the tissue distribution and analysed the methylation of the promoters. We identified Lhx9 of 1411 bp and Lhx9α of 1153-bp length, differing in the 3'-flanking region, encoding 399 and 330 amino acids, respectively. The Lhx9 gene was detected primarily in liver, ovary and heart with moderate expression in brain, pituitary, intestine and spleen, and low expression in the remaining examined tissues, while Lhx9α expression was high in heart, pituitary and liver, and low in spleen and stomach. Significantly higher Lhx9 expression was observed in ovary than in testis, with no differences in Lhx9α expression between testis and ovary observed. Bisulphite sequencing revealed significantly higher methylation in testis compared to ovary. The methylation level of CpG sites -733, -673, -615 and -594 exhibited significantly higher levels in testis than in ovary, which was negatively correlated with Lhx9 expression. The methylation and expression patterns suggested that promoter methylation suppressed expression of Lhx9 in A. davidianus.
Lhx9是一种LIM（以首次发现该结构域的前三种蛋白质命名，即Lin-11、Isl1和Mec-3）同源结构域蛋白，参与性腺的发育和分化。在本研究中，我们从大鲵中分离出全长Lhx9和Lhx9α，检测了其组织分布并分析了启动子的甲基化情况。我们鉴定出长度为1411 bp的Lhx9和1153 bp的Lhx9α，它们在3'侧翼区域有所不同，分别编码399和330个氨基酸。Lhx9基因主要在肝脏、卵巢和心脏中检测到，在脑、垂体、肠道和脾脏中有中度表达，在其余检测组织中表达较低，而Lhx9α在心脏、垂体和肝脏中表达较高，在脾脏和胃中表达较低。观察到卵巢中的Lhx9表达明显高于睾丸，睾丸和卵巢之间未观察到Lhx9α表达的差异。亚硫酸氢盐测序显示，与卵巢相比，睾丸中的甲基化明显更高。CpG位点-733、-673、-615和-594的甲基化水平在睾丸中明显高于卵巢，这与Lhx9表达呈负相关。甲基化和表达模式表明，启动子甲基化抑制了大鲵中Lhx9的表达。
