Function of de2f2 in development. M.V. Frolov 1, D.S. Huen 2, B.A.J. Ponder 3, M. Elsdon 3, M. Ashburner 2, K. Balczarek-Strang 1, N.J. Dyson 1. 1) Cancer Ctr, Massachusetts General Hosp, Charlestown, MA; 2) Dept. of Genetics, Univ. of Cambridge, UK; 3) Cambridge Institute of Medical Research, Cambridge, UK.
The E2F-DP heterodimeric transcription factor (E2F) plays a key role in the control of cell cycle progression by coordinating the expression of target genes thought to be essential for S phase initiation and completion, However, the most important in vivo functions of E2F regulation remain poorly understood. In Drosophila, there are two E2F family members, de2f1 and de2f2, and one dDP gene. In the previous studies, de2f1 and dDP were found to be positive regulators of the cell cycle and essential for fly development. However, differences in their respective phenotypes suggested that they have functions independent of each other. dE2F2 is the other known of dDP partner but little is known about the dE2F2 function in the cell. To gain insights into the biological role of dE2F2, we isolated a de2f2 mutant allele. Using a P-element insertion in the adjacent gene, dMPP6, a deletion of de2f2 was generated by two consecutive rounds of male recombination. In the first round, a rearranged chromosome carrying a deletion taking out both dMPP6 and de2f2 was isolated. In the next step, this deletion was used to generate a small duplication, which restores the sequences of dMPP6 but not de2f2. We will describe the phenotype of the dE2F2 deficient flies and present data on target gene expression and S-phase progression in the mutant. Finally, genetic interaction between de2f1 and de2f2 and the consequences of the loss of all E2F activity for fly development will be presented.