Construct: Amino acid replacement: P140S.
20.9% of flies carrying Cdk7P140S in a heterozygous Df(1)JB254 P{snf+,dhd+} background (the Df(1)JB254 chromosome is deficient for Cdk7, snf and dhd and snf and dhd function is provided by the P{snf+,dhd+} transgene) at the restrictive temperature show shape deformities and size reduction in the wing. No brittle bristles or cuticle defects are seen in these animals. 36.3% of flies carrying Cdk7P140S in a homozygous Df(1)JB254 P{snf+,dhd+} background at the restrictive temperature show shape deformities and size reduction in the wing, 16.3% have brittle bristles and 5% have cuticle defects. Animals carrying Cdk7P140S in a Df(1)JB254 P{snf+,dhd+} background do not show abnormal amounts of apoptosis in the imaginal discs or central nervous system.
Flies carrying Cdk7P140S in a Df(1)JB254 P{snf+,dhd+} background (referred to as "cdk7ts" flies) are fully viable at 18oC but are not viable at 27oC or above. After transfer of cdk7ts females to the restrictive temperature, many of the embryos laid during the first 36 hours will eclose as larvae, and most of those embryos that fail to eclose show defects late in development. Mutant embryos exhibit gradually earlier developmental arrest to a point where the embryonic nuclear division program fails to be initiated. cdk7ts females cease to lay eggs after 3-4 days at the restrictive temperature. When pupae are transferred to the restrictive temperature (29oC), viable cdk7ts adults continue to eclose for up to 3 days after the temperature shift. These adults are viable at 29oC but show progressively stronger defects in mitotically active tissues with increasing time spent at 29oC. The first defect seen in females is a depletion of follicle cells, followed by the appearance of cysts containing fewer than 16 germ cells.
When Df(1)JB254 ; Cdk7P140S ; P{snf+,dhd+} animals are shifted to 29[o]C, the size of the eye imaginal disc becomes smaller in proportion to the time that th animals are kept at this temperature. When maintained at 29[o]C for three days, BrdU incorporation is reduced.
Flies carrying Cdk7P140S in a heterozygous Df(1)JB254 P{snf+,dhd+} background (the Df(1)JB254 chromosome is deficient for Cdk7, snf and dhd and snf and dhd function is provided by the P{snf+,dhd+} transgene) at the restrictive temperature that are also carrying one copy of haync2, haync2rv2 or haync2rv8 show brittle bristle and cuticle defect phenotypes. Flies carrying Cdk7P140S in a heterozygous Df(1)JB254 P{snf+,dhd+} background at the restrictive temperature that are also carrying one copy of haync2rv7 have brittle bristles. The penetrance of the wing phenotypes (shape deformities and size reduction) seen in flies carrying Cdk7P140S in a heterozygous Df(1)JB254 P{snf+,dhd+} background at the restrictive temperature is increased if they are also carrying one copy of haync2rv8. These animals do not show abnormal amounts of apoptosis in the imaginal discs or central nervous system.
Cdk7P140S partially rescues Cdk7[-]
