homozygous intestinal stem cell (ISC) clones are lost over time. In wild-type clones, approximately 86-100% of ISC clones present on day 4 are maintained on day 14, while almost all Tsc1Q87X
homozygous clones present on day 4 are absent on day 14. The remaining ISC clones on day 14 generally contain fewer cells, indicating that the Tsc1Q87X
clones are under-proliferative. The mutant ISCs are also larger than in wild-type. The distribution of TUNEL, a marker for fragmented DNA, indicative of apoptosis, shows that Tsc1Q87X
mutant ISC clones do not undergo apoptosis. Treatment of Tsc1Q87X
ISC clone flies with rapamycin results in increased survival of the mutant ISC clones and rescues the enteroendocrine cell differentiation defects, in contrast to untreated cells.
Only approximately 7% of Tsc1Q87X
homozygous mutant intestinal stem cell (ISC) clones contain enteroendocrine cells, and later in development, these enteroendocrine cells are lost, indicating that Tsc1
is essential for enteroendocrine cell differentiation.
eyFLP/MARCM-generated clones of Tsc1Q87X
result in eye overgrowth.
mutant clones on the adult thorax exhibit double bristles, missing bristles, patches of bald cuticle, and delay or premature arrest of the cell cycle, as compared to controls.
mutant larvae appear to undergo precocious development.
Head capsule enlarged - bighead phenotype.
animals die as 2nd instar larvae. These animals survive until pupation if they are raised on food containing the rapamycin derivative RAD001, at a concentration of 30 μM. Somatic clones of Tsc1Q87X
in the developing eye cause strong overgrowth of the eye. The size of ommatidia in clones is increased relative to wild-type.
Eyes carrying homozygous Tsc1Q87X
clones are significantly larger than wild-type eyes with a substantial overrepresentation of mutant tissue over wild-type tissue. The individual facets of the eye as well as the interommatidial bristles are significantly larger in the mutant portions of the eye. Mutant ommatidia are larger than adjacent wild-type ommatidia. The cell bodies of individual mutant cells are enlarged, as are the rhabdomeres of mutant photoreceptor cells. In mosaic ommatidia, the larger rhabdomeres are always mutant, indicating that Tsc1
function is cell autonomous. Mutant ommatidia occasionally have missing or extra photoreceptor cells. Ommatidial misrotations are seen near clonal boundaries. Imaginal discs containing homozygous clones are significantly larger than wild type.