鸡PAPPA2基因在卵泡中的时空表达特性分析

Characteristics of Spatio-temporal Expression of PAPPA2 Gene in the Developing Follicles of Chickens

为探讨PAPPA2基因在鸡卵泡生长发育中的调控作用,以150日龄海兰褐蛋鸡为供试材料,采用相对定量RT-PCR方法对PAPPA2基因在鸡卵巢组织不同发育时期卵泡中的mRNA转录水平进行检测分析,并用免疫组织化学方法对PAPPA2蛋白质分子在鸡前等级卵泡中的时空表达模式进行了蛋白定位分析。结果表明:鸡PAPPA2基因mRNA在卵巢间质、各前等级卵泡和不同等级化的卵泡中均有表达,但也表现出其在不同卵泡组织中转录水平的差异性,其中,PAPPA2基因在间质组织、5~6 mm、6~7 mm、F2卵泡中的mRNA转录水平最高(P<0.05),而在4~5 mm前等级卵泡和F3卵泡中的mRNA表达量最低(P<0.05)。由此表明,鸡PAPPA2基因对处于不同阶段的卵泡生长发育发挥着不可或缺的调控功能,且表现出卵泡的不同生长发育程度可能与PAPPA2基因的转录水平之间有着剂量依赖关系。通过免疫组化检测结果可见,鸡PAPPA2蛋白质分子在卵巢间质组织、卵母细胞和颗粒细胞中均有表达,但在膜层细胞中未检测到其表达信号。初步推断,鸡PAPPA2分子可能以旁分泌或自分泌的方式在卵泡的生长发育过程中发挥着重要调节作用。

To investigate the regulatory role of PAPPA2 gene in chicken follicular growth and development,the expression abundances of PAPPA2 gene mRNA in the varied-size developing follicles sampled from the 150 d Hylan brown layers were determined by using relative quantitative RT-PCR method. It was found that PAPPA2 gene mRNA was expressed in the all sized follicles and stroma tissues and differential mRNA expression levels were exhibited among some groups sampled,wherein,the highest expression levels were observed in stroma,5-6 mm and 6-7 mm sized prehierarchal follicles and F2 follicles（ P〈0. 05）,on the contrary,the lowest levels were determined in 4-5 mm sized and F3 follicles（ P〈0. 05）. The current results indicated that the PAPPA2 gene may play an indispensable role in different developmental stages of the varied-sized follicles in a dosage-dependent manner. The expression of PAPPA2 protein was detected in the stroma,oocytes and granulosacells by immunohistochemical analysis,but no positive expression signal was probed in the theca cells. It was inferred that chicken PAPPA2 protein amy exert a critical biological function in regulating the follicular growth and development in a paracrine and/or autocrine manner. The present data provide reference for further exploring the exact roles and molecular mechanisms of PAPPA2 gene in the regulation of follicular growth and development in hen ovary.