Developmental and protein modification defects caused by mutations in the Drosophila gene l(3)c21R.

A temperature-sensitive Drosophila mutation, l(3)c21RRW630 (abbreviated RW630), has been previously shown to have biochemical as well as developmental defects. To analyze further the relationship between the biochemical and developmental defects, recombinational mapping, deletion analysis, and complementation studies with other l(3)c21R alleles were performed. These experiments showed that the biochemical and developmental defects in RW630 can be attributed to a single mutation. Four non-temperature-sensitive l(3)c21R alleles were found to have biochemical defects similar to those seen in RW630 at restrictive temperature. In RW630 and in these four other l(3)c21R alleles, the severity of expression of the biochemical and the developmental defects was closely correlated. Temperature-shift studies of the expression of the RW630 maternal lethal effect on embryogenesis in females transheterozygous for RW630 and other l(3)c21R alleles yielded results which indicated that these defects must accumulate over a period of time before the maternal lethal effect can be detected. These data provide further support for the hypothesis that defects in protein modification produce developmental defects in l(3)c21R mutants.