mRNA differential display was established by Liang and Pardee in 1992 for the purpose of displaying the mRNA differences between two tissues. The early embryonic development in animals is primarily controlled by the maternal RNAs stored in egg. These mRNAs are being degraded as the development proceeds. In some animals, such as fish and amphibian, new transcripts do not appear until the midblastula stage (midblastula transition, MBT). In other animals, for example in mouse, the zygotic genes are expressed during very early stages of development. The mRNA programmed synthesis and degradation during embryonic development controls the cell differentiation, germlayer formation and pattern formation. All these mRNA changes could be displayed side by side as cDNA band differences by mRNA differential display and the genes corresponding to these differential mRNAs could thus be obtained.
为了分离鼠精子发生时期表达的基因，本文采用mRNA差异显示法，以鼠的粗线期卵母细胞为对照，检测了出生后60天和16天鼠的睾丸，得到12个有差异的片段（Fig.l&Table1)。克隆测序表明，其中5个与已知基因非常吻合，另外6个与一些未知功能的cDNA,ESTs有较高的同源性，只有1个与已知序列没有同源性，Northern杂交分析显示spl和sp8主要在成年鼠睾丸表达（Fig.4B），采用5’RACE对sp1的cDNA进行了全长分析，该基因编码一个推测是高度磷酸化蛋白的541个氨基酸（Fig.2)，其中包括一个核定位信号，无论在核苷酸水平上，还是在氨基酸水平上均没有明显的同源性，仅在2个蛋白区有少量同源氨基酸（Fig.3)。该基因在20-60天龄鼠的睾丸均有表达，并且具有很高的组织特异性-只在睾丸里表达（Fig.4A)。因而，这个基因有可能参与减数分裂及其以后的整个过程，可以认为这是一个新基因，我们把它命名为peat(predominantly expressed in adult testis)。
