Document Detail

An unexpected role for the clock protein timeless in developmental apoptosis.
MedLine Citation:
PMID:  21359199     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Programmed cell death is critical not only in adult tissue homeostasis but for embryogenesis as well. One of the earliest steps in development, formation of the proamniotic cavity, involves coordinated apoptosis of embryonic cells. Recent work from our group demonstrated that c-Src protein-tyrosine kinase activity triggers differentiation of mouse embryonic stem (mES) cells to primitive ectoderm-like cells. In this report, we identified Timeless (Tim), the mammalian ortholog of a Drosophila circadian rhythm protein, as a binding partner and substrate for c-Src and probed its role in the differentiation of mES cells.
METHODOLOGY/PRINCIPAL FINDINGS: To determine whether Tim is involved in ES cell differentiation, Tim protein levels were stably suppressed using shRNA. Tim-defective ES cell lines were then tested for embryoid body (EB) formation, which models early mammalian development. Remarkably, confocal microscopy revealed that EBs formed from the Tim-knockdown ES cells failed to cavitate. Cells retained within the centers of the failed cavities strongly expressed the pluripotency marker Oct4, suggesting that further development is arrested without Tim. Immunoblots revealed reduced basal Caspase activity in the Tim-defective EBs compared to wild-type controls. Furthermore, EBs formed from Tim-knockdown cells demonstrated resistance to staurosporine-induced apoptosis, consistent with a link between Tim and programmed cell death during cavitation.
CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a novel function for the clock protein Tim during a key stage of early development. Specifically, EBs formed from ES cells lacking Tim showed reduced caspase activity and failed to cavitate. As a consequence, further development was halted, and the cells present in the failed cavity remained pluripotent. These findings reveal a new function for Tim in the coordination of ES cell differentiation, and raise the intriguing possibility that circadian rhythms and early development may be intimately linked.
Linda P O'Reilly; Simon C Watkins; Thomas E Smithgall
Related Documents :
3173379 - The interaction of triethyl lead with tubulin and microtubules.
18508459 - The kinetochore and spindle checkpoint in mammals.
2175259 - The effects of delta-9-tetrahydrocannabinol on actin microfilaments.
2277069 - Microinjection of villin into cultured cells induces rapid and long-lasting changes in ...
17707899 - Effects of hydrostatic pressure on microtubule organization and cell cycle in gynogenet...
12058019 - The adenomatous polyposis coli protein unambiguously localizes to microtubule plus ends...
19036799 - A critical time window of sry action in gonadal sex determination in mice.
721899 - Non-reciprocal contact inhibition of locomotion of chick embryonic choroid fibroblasts ...
22843029 - Cell viability of microencapsulated bifidobacterium animalis subsp. lactis under freeze...
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2011-02-17
Journal Detail:
Title:  PloS one     Volume:  6     ISSN:  1932-6203     ISO Abbreviation:  PLoS ONE     Publication Date:  2011  
Date Detail:
Created Date:  2011-03-01     Completed Date:  2011-09-01     Revised Date:  2013-06-30    
Medline Journal Info:
Nlm Unique ID:  101285081     Medline TA:  PLoS One     Country:  United States    
Other Details:
Languages:  eng     Pagination:  e17157     Citation Subset:  IM    
Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Amino Acid Sequence
Apoptosis / drug effects,  genetics*
Body Patterning / drug effects,  genetics*
Cell Cycle Proteins / antagonists & inhibitors,  genetics,  metabolism,  physiology*
Cell Differentiation / drug effects,  genetics,  physiology
Cells, Cultured
Embryonic Stem Cells / drug effects,  metabolism,  physiology
Gene Expression Regulation, Developmental / drug effects,  physiology
Gene Knockout Techniques
Intracellular Signaling Peptides and Proteins / antagonists & inhibitors,  genetics,  metabolism,  physiology*
Molecular Sequence Data
Period Circadian Proteins / genetics,  metabolism,  physiology
RNA, Small Interfering / pharmacology
Grant Support
Reg. No./Substance:
0/Cell Cycle Proteins; 0/Intracellular Signaling Peptides and Proteins; 0/Period Circadian Proteins; 0/RNA, Small Interfering; 0/Timeless protein, mouse

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

Previous Document:  Distinct early molecular responses to mutations causing vLINCL and JNCL presage ATP synthase subunit...
Next Document:  Generation of trophoblast stem cells from rabbit embryonic stem cells with BMP4.