Figure 4. Drosophila with H3K36R or H3K36A mutant chromatin arrest development after completion of embryogenesis.
(A) Ventral views of cuticles from wildtype (wt), H3K36R, or H3K36A mutant embryos. Note that the cuticle pattern of the mutant animals is indistinguishable from that of the wt embryo. Below: for each genotype, the fraction of embryos that developed into larvae, pupae, pharate adults or viable adults is listed. The fraction was determined by monitoring the development of collected hatched 1st instar larvae (wt: n = 300, H3K36R (Matera strain): n = 2000) or unhatched embryos (H3K36R (strain generated in this study): n = 200; H3K36A: n = 200). The GFP marker on the Balancer chromosomes was used for identifying H3K36R and H3K36A mutants. See Materials and methods for further information and discussion. (B) Dorsal views of the posterior portion of the thorax and of the abdomen. From 2000 hatched H3K36R mutant 1st instar larvae, a total of 18 pharate adults was recovered. Most H3K36R mutant pharate adults showed a relatively normal overall body patterning apart from the homeotic transformations illustrated below. (C) Frontal view of adult heads illustrating the antenna-to-leg transformation in H3K36R mutant pharate adults. The antenna-to-leg transformation in H3K36R mutant animals ranged from mild (arrows) to more extensive transformations with formation of leg-like structures such as in this extreme case (arrowheads). (D) The sex comb in males is normally only present on the protoracic (L1) legs (arrowheads). Among the H3K36R mutant pharate adult males recovered (n = 13), five showed one or several extra sex comb teeth (arrow) on the meso- (L2) or meta-thoracic (L3) legs. Extra sex comb teeth in adults are a hallmark phenotype of polycomb mutants.