Misra S, Rio D C
Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142.
Cell. 1990 Jul 27;62(2):269-84. doi: 10.1016/0092-8674(90)90365-l.
Drosophila P transposable elements encode two proteins, an 87 kd transposase protein and a 66 kd protein that has been hypothesized to repress transposition. We have made germline transformants carrying modified P element derivatives that encode only the 66 kd protein and shown that these elements repress transposase activity in both the germline and the soma. The position of these elements in the genome quantitatively affected their ability to negatively regulate transposase and to express the 66 kd protein. Single 66 kd element-containing strains did not exhibit the maternal inheritance of P cytotype characteristic of P strains. However, we demonstrated that a true P strain produced higher levels of the 66 kd protein during oogenesis than single 66 kd P elements. Thus, the expression of the 66 kd repressor during oogenesis may be a major determinant of the maternal effect of P cytotype.
果蝇P转座因子编码两种蛋白质，一种87kd的转座酶蛋白和一种66kd的蛋白，据推测该蛋白可抑制转座作用。我们构建了携带仅编码66kd蛋白的修饰P因子衍生物的种系转化体，并表明这些因子在种系和体细胞中均抑制转座酶活性。这些因子在基因组中的位置定量地影响它们负调控转座酶和表达66kd蛋白的能力。单个含66kd因子的菌株未表现出P菌株特有的P细胞型母系遗传特征。然而，我们证明，一个真正的P菌株在卵子发生过程中产生的66kd蛋白水平高于单个含66kd的P因子。因此，卵子发生过程中66kd阻遏物的表达可能是P细胞型母系效应的主要决定因素。
