Related Experiment Videos
Mutagen sensitivity and suppression of position-effect variegation result from mutations in mus209, the Drosophila
D S Henderson1, S S Banga, T A Grigliatti
1Section of Molecular and Cellular Biology, University of California, Davis 95616.
Abstract:
The mus209B1 mutant of Drosophila melanogaster exhibits a complex pleiotropy of temperature-sensitive (ts) lethality, hypersensitivity to DNA-damaging agents such as ionizing radiation and methyl methanesulfonate, suppression of position-effect variegation (PEV), and female sterility. Our discovery that mus209 encodes proliferating cell nuclear antigen (PCNA), which is an indispensable component of the DNA replication apparatus, suggests that alterations to chromosome replication may underlie that pleiotropy. Nine lethal mutations, three of them ts, genetically define the Pcna locus. Temperature shift studies reveal that the vital function of PCNA is required throughout virtually all stages of fly development, and that maternally encoded PCNA is essential for embryogenesis. All three ts mutants strongly suppress PEV, which suggests a role for PCNA in chromatin assembly or modification.
Insights
The Drosophila mus209 gene encodes proliferating cell nuclear antigen (PCNA), crucial for DNA replication. Mutations in PCNA cause developmental defects, DNA repair issues, and sterility, highlighting its essential role.
Area of Science:
- Molecular Biology
- Genetics
- Developmental Biology
Background:
- The mus209B1 mutant in Drosophila melanogaster displays pleiotropy, including temperature-sensitive lethality and DNA damage hypersensitivity.
- This mutant's characteristics suggested a role in DNA replication or repair processes.
Purpose of the Study:
- To identify the gene responsible for the mus209B1 mutant phenotype.
- To investigate the function of the identified gene product in DNA replication and its impact on development and chromatin structure.
Main Methods:
- Genetic analysis of the mus209B1 mutant.
- Identification of the mus209 gene and its encoded protein.
- Temperature shift experiments to assess developmental requirements.
- Analysis of position-effect variegation (PEV) suppression.
Main Results:
- The mus209 gene was identified as encoding proliferating cell nuclear antigen (PCNA).
- PCNA is essential throughout Drosophila development, with maternal contribution vital for embryogenesis.
- PCNA is required for DNA replication and plays a role in chromatin assembly or modification, as indicated by PEV suppression.
Conclusions:
- PCNA is indispensable for DNA replication and essential for viability throughout Drosophila development.
- Alterations in PCNA function can lead to pleiotropic effects, including developmental lethality, DNA repair defects, and sterility.
- PCNA's role extends to chromatin dynamics, influencing processes like PEV suppression.