Shattered is a new rough eye mutant which interact with roughex, string and fizzy-related. M. Tanaka-Matakatsu , B. Thomas. Lab Biochem, NCI/NIH, Bethesda, MD.

   The Drosophila compound eye is a good model system to analyze the coordinate regulation of cell cycle progression and cellular differentiation. shattered (shtd) mutations were isolated in a general screen for X-linked rough eye mutations. Genetically, shtd interacts with the Drosophila cdc25 homologue, string, and the negative regulator of mitotic cyclins, fizzy-related (Sigrist and Lehner). Histochemically, cells within the developing eye disc of shtd mutants show an increase in BrdU-incorporated S phase cells and phospho-Histone H3 positive cells behind the morphogenetic furrow (MF). The mitotic CyclinB expression pattern is altered, and Dpp, Scabrous and Rough are missexpressed, with some cells co-expressing these markers with CyclinB. These phenotypes are similar to those seen in roughex (rux) mutants that plays a key role in regulating cell cycle progression in the developing eye (Thomas et al. 1994). Also, double mutants of rux and shtd shows similar phenotypes. Like the rux mutation, shtd also contains multiple R8 cells in an ommatidium. These data indicate that shtd might play a role in regulating cell cycle progression and cellular differentiation. To identify the shtd gene, a new allele was isolated from an EP element local hop. The EP allele is caused by a 33Kbp deletion. At least 7 EST clones exist in this region. Some DNA regions within this deletion show polymorphisms between shtd EMS and gamma ray alleles. Further molecular and phenotypic analysis of the shtd gene will be discussed. References Thomas et al, Cell 77(7): 1003-14 (1994) Sigrist and Lehner, Cell 90(4): 671-81(1997).