New Mutations in the 5' Region of the Gene Affect Oogenesis.

The Notch pathway is an important and evolutionarily conserved signaling system involved in the development of multicellular organisms. Notch signaling plays an important role in the regulation of proliferation and differentiation of many cell types. In this study, we report new aspects of gene participation in oogenesis using our previously generated mutations. The mutations consist of an insertion of an auxiliary element of a transgene construct into the first intron of the gene and a series of directed deletions within the 5' regulatory region of . We showed that some of these mutations affect oogenesis. This insertion, either alone or in combination with the deletion of an insulator sequence, led to lower expression of in the ovaries. As a result, the formation of egg chambers was disturbed in middle oogenesis. These abnormalities have not been described previously and imply one more function of in oogenesis. It can be assumed that is associated with not only follicular epithelium morphogenesis but also cellular mechanisms of oocyte growth.