CycE^hs.PR flies raised at 29^oC have defective egg chambers with fewer or extra cystocyte divisions, fusion of egg chambers, abnormal polyploidy and apoptosis. In cases with very reduced germ cell numbers per cyst, the remaining cell exhibits enormous polyploidization.

2 hours after CycE^hs.PR is expressed in third instar larval eye imaginal disc by heatshocking, G₁ arrested cells in the anterior part of the morphogenetic furrow (MF) and cells in the post MF S phase region are induced into S phase. Cells in the posterior part of the MF remain arrested in G₁.

Embryos in which CycE^hs.PR is expressed in early stage 12 using heat shock undergo a single ectopic round of cell division within 1 hour of the heat shock. These embryos start germband retraction normally, but take approximately 30 minutes longer than wild-type heat-shocked embryos to complete retraction. Clusters of cells are often seen floating in the intervitelline space above the amnioserosa, in contrast to wild type. Only 15% of the embryos expressing CycE^hs.PR hatch within 24 hours of the heat shock, in contrast to 83% of wild-type heat-shocked embryos. 25% of the heat-shocked embryos expressing CycE^hs.PR reach adulthood. The embryos that fail to hatch show defects in germband retraction and epidermal integrity (as seen by yolk leaking into the intervitelline space). Abdominal segments A3 and A4 show an approximately 14% increase in the number of denticle hairs per segment. The increase is graded within each denticle belt, with the most anterior denticle row having the most extra denticles, and the number of extra denticles decreasing more posteriorly. The denticle rows are wider and the denticles are closer together than normal. Embryos in which CycE^hs.PR is expressed in early stage 12 using heat shock show a 62% increase in epidermal cell density (in the dorsolateral region of abdominal segments A3 and A4, midway between the segment borders) within 1 hour of the heat shock compared to wild-type heat-shocked embryos. By 2 hours after the heat shock, the cell density has decreased to 57% above wild type, and by 4 hours after the heat shock, the cell density is 18% above wild type. The increase in cell density is also seen in first instar larvae. The pattern of cell death in embryos in which CycE^hs.PR is expressed in early stage 12 using heat shock is initially very similar to that of wild-type heat-shocked embryos. However, there is a large increase in cell death in CycE^hs.PR embryos at the completion of germband retraction. This increase in cell death in each segment first appears adjacent to the segment borders, and then spreads into the middle of the segment.

Expression of CycE^hs.PR in starved larvae using heat shock is sufficient to drive endoreplicating cells into S phase, as assayed by BrdU incorporation. Neuroblasts do not incorporate BrdU in these larvae.

Flies exhibit ectopic S phases in the eye disc, coexpression of rux^hs.PT fails to suppress this phenotype. Scer\GAL4^prd.RG1-mediated expression of rux^Scer\UAS.cTa in the embryonic somatic cells is unable to inhibit CycE-dependent processes, ectopic entry into S phase.

CycE expression in the eye imaginal disc triggers entry of the majority of the G₁ cells anterior to the morphogenetic furrow into S phase. In addition the band of S phase cells posterior to the furrow is wider and contains more labeled cells than in the control. The narrow band of cells in the morphogenetic furrow are not affected, though there is a general increase in the number of cells in S phase throughout the disc. At least some of the cells that prematurely enter S phase proceed through the complete, extra, cell cycle. When allowed to develop into adults abnormal eyes result. Eyes become roughened, ommatidia are irregular in size and position and photoreceptor complement, and the interommatidial bristles are increased in number.

CycE^hs.PR is a suppressor of decreased occurrence of cell division | larval stage phenotype of trol^p6

CycE^hs.PR is a suppressor of decreased occurrence of cell division | larval stage phenotype of trol¹⁰⁴

CycE^hs.PR is a suppressor of decreased occurrence of cell division | larval stage phenotype of trol^p4

CycE^hs.PR is a suppressor of decreased occurrence of cell division | larval stage phenotype of trol^p5

CycE^hs.PR is a suppressor | partially of decreased occurrence of cell division | third instar larval stage phenotype of eve³/eve[+], trol¹³

CycE^hs.PR is a suppressor of decreased occurrence of cell division | larval stage phenotype of trol^sd

CycE^hs.PR is a suppressor of neuroblast | larval stage phenotype of trol^p6

CycE^hs.PR is a suppressor of neuroblast | larval stage phenotype of trol¹⁰⁴

CycE^hs.PR is a suppressor of neuroblast | larval stage phenotype of trol^p4

CycE^hs.PR is a suppressor of neuroblast | larval stage phenotype of trol^p5

CycE^hs.PR is a suppressor of larval brain & neuroblast phenotype of eve³/eve[+], trol¹³

CycE^hs.PR is a suppressor of cell cycle phenotype of mTor^ΔP

CycE^hs.PR is a suppressor of neuroblast & larval brain phenotype of trol^sd