For propagation in fission yeast, successful recovery of complementing plasmids requires adaptation of pooled plasmids from a Drosophila embryonic cDNA library. This is achieved by introducing an ars1-LEU2 DNA fragment into the vector. The gene that encodes the Drosophila cdc2 homolog maps to a single locus in the Drosophila genome at 31E on chromosome 2. In contrast, mRNA levels are somewhat lower during the short quiescent interval accompanying cellularization, and still much lower in late embryos, when only a few cells continue to divide. The transcripts present in early embryos are maternal .
Signals become gradually restricted to the developing nervous system after germband retraction.
Effects of Mutation or Deletion Mutations have been identified in the Drosophila cdc2 gene. Sequence analysis of amorphic alleles reveals non-conservative exchanges in evolutionary conserved positions. These alleles cause lethality at the larval-pupal interphase due to the absence of imaginal tissues. Embryonic lethality results when the maternal cdc2 contribution is reduced through the use of a temperature-sensitive allele. The reversible block of the mitotic proliferation observed in the peripheral nervous system of mutant embryos occurs exclusively in the G2-phase.