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Updated: Jan 11, 2026
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cul-1 is required for cell cycle exit in C. elegans and identifies a novel gene family
E T Kipreos1, L E Lander, J P Wing
1Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Abstract:
The gene cul-1 (formerly lin-19) is a negative regulator of the cell cycle in C. elegans. Null mutations cause hyperplasia of all tissues. cul-1 is required for developmentally programmed transitions from the G1 phase of the cell cycle to the GO phase or the apoptotic pathway. Moreover, the mutant phenotype suggests that G1-to-S phase progression is accelerated, overriding mechanisms for mitotic arrest and producing abnormally small cells. Significantly, diverse aspects of cell fate and differentiation are unaffected in cul-1 mutants. cul-1 represents a conserved family of genes, designated cullins, with at least five members in nematodes, six in humans, and three in budding yeast.
Insights
The cell cycle regulator gene cul-1 controls normal tissue growth in C. elegans. Mutations lead to uncontrolled cell proliferation and developmental defects, highlighting its crucial role in cell cycle regulation.
Area of Science:
- Developmental Biology
- Cell Biology
- Genetics
Background:
- The cell cycle is a fundamental process regulating cell division and growth.
- Negative regulators of the cell cycle are crucial for preventing uncontrolled proliferation.
- The C. elegans gene cul-1 (formerly lin-19) has been identified as a potential cell cycle regulator.
Purpose of the Study:
- To investigate the function of the cul-1 gene in C. elegans development.
- To determine the role of cul-1 in cell cycle regulation and its impact on tissue growth.
- To explore the consequences of cul-1 loss-of-function mutations.
Main Methods:
- Analysis of null mutations in the cul-1 gene in C. elegans.
- Phenotypic characterization of cul-1 mutants, including tissue hyperplasia and cell cycle progression.
- Comparison of cell fate and differentiation in wild-type and cul-1 mutant organisms.
Main Results:
- Null mutations in cul-1 result in hyperplasia across all tissues in C. elegans.
- cul-1 is essential for programmed transitions from the G1 phase to GO or apoptosis.
- Mutant phenotypes indicate accelerated G1-to-S phase progression, bypassing mitotic arrest and leading to small cells, while cell fate remains unaffected.
Conclusions:
- cul-1 acts as a critical negative regulator of the cell cycle in C. elegans.
- Loss of cul-1 function disrupts normal cell cycle control, leading to hyperplasia and developmental abnormalities.
- cul-1 belongs to the conserved cullin family of genes, suggesting a conserved role in cell cycle regulation across species.
