The Small Subunit Processome Is Required for Cell Cycle Progression at G1
AUTOR(ES)
Bernstein, Kara A.
FONTE
The American Society for Cell Biology
RESUMO
Without ribosome biogenesis, translation of mRNA into protein ceases and cellular growth stops. We asked whether ribosome biogenesis is cell cycle regulated in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, and we determined that it is not regulated in the same manner as in metazoan cells. We therefore turned our attention to cellular sensors that relay cell size information via ribosome biogenesis. Our results indicate that the small subunit (SSU) processome, a complex consisting of 40 proteins and the U3 small nucleolar RNA necessary for ribosome biogenesis, is not mitotically regulated. Furthermore, Nan1/Utp17, an SSU processome protein, does not provide a link between ribosome biogenesis and cell growth. However, when individual SSU processome proteins are depleted, cells arrest in the G1 phase of the cell cycle. This arrest was further supported by the lack of staining for proteins expressed in post-G1. Similarly, synchronized cells depleted of SSU processome proteins did not enter G2. This suggests that when ribosomes are no longer made, the cells stall in the G1. Therefore, yeast cells must grow to a critical size, which is dependent upon having a sufficient number of ribosomes during the G1 phase of the cell cycle, before cell division can occur.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=524768Documentos Relacionados
- Calmodulin is required for cell-cycle progression during G1 and mitosis.
- Cellulose Synthesis Is Coupled to Cell Cycle Progression at G1 in the Dinoflagellate Crypthecodinium cohnii
- Human cytomegalovirus infection inhibits cell cycle progression at multiple points, including the transition from G1 to S.
- The Small-Subunit Processome Is a Ribosome Assembly Intermediate
- Human Cytomegalovirus 86-Kilodalton IE2 Protein Blocks Cell Cycle Progression in G1