Document Detail

Integration of light signals by the retinoblastoma pathway in the control of S phase entry in the picophytoplanktonic cell Ostreococcus.
MedLine Citation:
PMID:  20502677     Owner:  NLM     Status:  MEDLINE    
Although the decision to proceed through cell division depends largely on the metabolic status or the size of the cell, the timing of cell division is often set by internal clocks such as the circadian clock. Light is a major cue for circadian clock entrainment, and for photosynthetic organisms it is also the main source of energy supporting cell growth prior to cell division. Little is known about how light signals are integrated in the control of S phase entry. Here, we present an integrated study of light-dependent regulation of cell division in the marine green alga Ostreococcus. During early G1, the main genes of cell division were transcribed independently of the amount of light, and the timing of S phase did not occur prior to 6 hours after dawn. In contrast S phase commitment and the translation of a G1 A-type cyclin were dependent on the amount of light in a cAMP-dependent manner. CyclinA was shown to interact with the Retinoblastoma (Rb) protein during S phase. Down-regulating Rb bypassed the requirement for CyclinA and cAMP without altering the timing of S phase. Overexpression of CyclinA overrode the cAMP-dependent control of S phase entry and led to early cell division. Therefore, the Rb pathway appears to integrate light signals in the control of S phase entry in Ostreococcus, though differential transcriptional and posttranscriptional regulations of a G1 A-type cyclin. Furthermore, commitment to S phase depends on a cAMP pathway, which regulates the synthesis of CyclinA. We discuss the relative involvements of the metabolic and time/clock signals in the photoperiodic control of cell division.
Mickael Moulager; Florence Corellou; Valérie Vergé; Marie-Line Escande; François-Yves Bouget
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-05-20
Journal Detail:
Title:  PLoS genetics     Volume:  6     ISSN:  1553-7404     ISO Abbreviation:  PLoS Genet.     Publication Date:  2010 May 
Date Detail:
Created Date:  2010-05-26     Completed Date:  2010-09-13     Revised Date:  2013-05-29    
Medline Journal Info:
Nlm Unique ID:  101239074     Medline TA:  PLoS Genet     Country:  United States    
Other Details:
Languages:  eng     Pagination:  e1000957     Citation Subset:  IM    
Université Pierre et Marie Curie, Paris 06, France.
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MeSH Terms
Plankton / cytology,  metabolism,  radiation effects*
Retinoblastoma Protein / metabolism*
S Phase / radiation effects*
Reg. No./Substance:
0/Retinoblastoma Protein

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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