Document Detail


Regulation of the Chlamydomonas cell cycle by a stable, chromatin-associated retinoblastoma tumor suppressor complex.
MedLine Citation:
PMID:  20978220     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We examined the cell cycle dynamics of the retinoblastoma (RB) protein complex in the unicellular alga Chlamydomonas reinhardtii that has single homologs for each subunit-RB, E2F, and DP. We found that Chlamydomonas RB (encoded by MAT3) is a cell cycle-regulated phosphoprotein, that E2F1-DP1 can bind to a consensus E2F site, and that all three proteins interact in vivo to form a complex that can be quantitatively immunopurified. Yeast two-hybrid assays revealed the formation of a ternary complex between MAT3, DP1, and E2F1 that requires a C-terminal motif in E2F1 analogous to the RB binding domain of plant and animal E2Fs. We examined the abundance of MAT3/RB and E2F1-DP1 in highly synchronous cultures and found that they are synthesized and remain stably associated throughout the cell cycle with no detectable fraction of free E2F1-DP1. Consistent with their stable association, MAT3/RB and DP1 are constitutively nuclear, and MAT3/RB does not require DP1-E2F1 for nuclear localization. In the nucleus, MAT3/RB remains bound to chromatin throughout the cell cycle, and its chromatin binding is mediated through E2F1-DP1. Together, our data show that E2F-DP complexes can regulate the cell cycle without dissociation of their RB-related subunit and that other changes may be sufficient to convert RB-E2F-DP from a cell cycle repressor to an activator.
Authors:
Bradley J S C Olson; Michael Oberholzer; Yubing Li; James M Zones; Harjivan S Kohli; Katerina Bisova; Su-Chiung Fang; Jill Meisenhelder; Tony Hunter; James G Umen
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2010-10-26
Journal Detail:
Title:  The Plant cell     Volume:  22     ISSN:  1532-298X     ISO Abbreviation:  Plant Cell     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-11-30     Completed Date:  2011-04-14     Revised Date:  2012-05-07    
Medline Journal Info:
Nlm Unique ID:  9208688     Medline TA:  Plant Cell     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3331-47     Citation Subset:  IM    
Affiliation:
Plant Molecular and Cellular Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Data Bank Information
Bank Name/Acc. No.:
GENBANK/AAK68064;  AAV41810;  AAV68604;  DQ417491;  DQ417492;  GU784915;  U54830; RefSeq/NP_566417;  XP_002948442;  XP_002955099
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MeSH Terms
Descriptor/Qualifier:
Cell Cycle*
Chlamydomonas / cytology*,  genetics,  metabolism
Chromatin / metabolism*
E2F Transcription Factors / genetics,  metabolism
Gene Expression Regulation, Plant
Molecular Sequence Data
Phosphoproteins / genetics,  metabolism
Phosphorylation
Plant Proteins / metabolism*
Protozoan Proteins / genetics,  metabolism*
Recombinant Proteins / genetics,  metabolism
Retinoblastoma Protein / genetics,  metabolism*
Transcription Factor DP1 / genetics,  metabolism
Two-Hybrid System Techniques
Grant Support
ID/Acronym/Agency:
CA-832683/CA/NCI NIH HHS; GM086037/GM/NIGMS NIH HHS; R01 CA082683-13/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Chromatin; 0/E2F Transcription Factors; 0/Phosphoproteins; 0/Plant Proteins; 0/Protozoan Proteins; 0/Recombinant Proteins; 0/Retinoblastoma Protein; 0/Transcription Factor DP1; 0/mat3 protein, Chlamydomonas
Comments/Corrections

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