Dominant Drop mutants are gain-of-function alleles of the muscle segment homeobox gene (msh) whose overexpression leads to the arrest of eye development
Abstract
Dominant Drop (Dr) mutations are nearly eyeless and have additional recessive phenotypes including lethality and patterning defects in eye and sensory bristles due to cis-regulatory lesions in the cell cycle regulator string (stg). Genetic analysis demonstrates that the dominant small eye phenotype is the result of separate gain-of-function mutations in the closely linked muscle segment homeobox (msh) gene, encoding a homeodomain transcription factor required for patterning of muscle and nervous system. Reversion of the Dr(Mio) allele was coincident with the generation of lethal loss-of-function mutations in msh in cis, suggesting that the dominant eye phenotype is the result of ectopic expression. Molecular genetic analysis revealed that two dominant Dr alleles contain lesions upstream of the msh transcription start site. In the Dr(Mio) mutant, a 3S18 retrotransposon insertion is the target of second-site mutations (P-element insertions or deletions) which suppress the dominant eye phenotype following reversion. The pattern of 3S18 expression and the absence of msh in eye imaginal discs suggest that transcriptional activation of the msh promoter accounts for ectopic expression. Dr dominant mutations arrest eye development by b...Continue Reading
References
Expanded polyglutamine protein forms nuclear inclusions and causes neural degeneration in Drosophila
Citations
Related Concepts
Related Feeds
Apoptosis
Apoptosis is a specific process that leads to programmed cell death through the activation of an evolutionary conserved intracellular pathway leading to pathognomic cellular changes distinct from cellular necrosis