Cloning and analysis of the dec-1 female-sterile locus, a gene required for proper eggshell morphogenesis in Drosophila
Female-sterile mutations at the dec-1 (defective chorion) locus of Drosophila severely disrupt organization of the eggshell late in oogenesis. Previous characterization of dec-1 mutations has correlated the defects with failure to accumulate an early eggshell protein which undergoes multiple cleavages during eggshell morphogenesis. A temporal coincidence between a cleavage late in eggshell morphogenesis and the extreme loss of eggshell organization in dec-1 mutants suggests that dec-1 proteins may provide an essential framework for assembly of eggshell proteins synthesized and secreted later in oogenesis. Furthermore, an exceptionally large number of mutant alleles of the locus have been recovered, with a complex pattern of genetic complementation. To enable further study of the regulation and processing of dec-1 products, the locus was molecularly cloned and characterized. Genomic DNA from the region cytogenetically determined to include the dec-1 locus was isolated. Eggchamber transcripts from this region were analyzed and a gene encoding a transcript compatible with the expected size and temporal accumulation of a dec-1 messenger RNA was identified. Analysis of genomic rearrangements associated with the locus verified its identity. Two transcripts from the locus have been identified and characterized using cDNA clone, Northern blot and RNase protection analyses. A 4.0 kb transcript accumulates maximally in stages 9-10, when the primary follicle cell protein associated with dec-1 mutations is synthesized. A second transcript of 5.8 kb, generated by alternative splicing, accumulates during stages 11-12. Results of the molecular characterization of the dec-1 locus are considered in light of previous analysis of dec-1 mutations and wild-type dec-1 proteins.
Robert John Hawley,
"Cloning and analysis of the dec-1 female-sterile locus, a gene required for proper eggshell morphogenesis in Drosophila"
(January 1, 1987).
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