Linked Life Data

11922601

Source:http://linkedlifedata.com/resource/pubmed/id/11922601

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2002-3-29
pubmed:abstractText
Megakaryocytes undergo an unusual cell cycle during differentiation that results in polyploidy through largely unknown mechanism(s). It has been shown that serine phosphorylation of oncoprotein 18 (Op18) is required for cell cycle progression specifically at the G2/M transition. Moreover, mutant forms of Op18 that are defective in one or more of the four serine residues induce G2/M arrest and subsequent polyploidization. Op18 phosphorylation is rapidly induced with phorbol myristate acetate (PMA) treatment in a wide range of human cells. In this study, we investigated the role of Op18 in PMA induced polyploidization during megakaryocyte differentiation of the human erythroleukemia cell line. Crucial to the molecular analysis of megakaryocyte differentiation, is the ability to fractionate cell populations with different ploidy levels. We have utilized cell elutriation as a fractionation strategy to analyze Op18 expression in synchronized cell subpopulations in different phases of the cell cycle or with progressive megakaryocyte polyploidization. In the absence of PMA, increased phosphorylation of Op18 was observed in HEL cells during cell cycle progression, as for other proliferating cells. However, in contrast to Jurkat leukemia cells chosen as control, HEL cells exhibited a lack of Op18 phosphorylation in response to PMA, which was accompanied by polyploidization and differentiation along the megakaryocytic lineage. To further determine the role of Op18 in polyploidization, HEL cells were transfected with different Op18 expression constructs. Differences in cell survival and polyploidization were observed between high and low Op18 expressors. An increased Op18 level reduced cell survival during the early stage of PMA induced megakaryocyte differentiation, but enhanced polyploidization efficiency. Our findings suggest that maintenance of a high level of unphosphorylated Op18 is required for efficient polyploidization during the differentiation program of megakaryocytes.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1615-9853
pubmed:author
pubmed:issnType
Print
pubmed:volume
1
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1415-23
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Oncoprotein 18 levels and phosphorylation mediate megakaryocyte polyploidization in human erythroleukemia cells.
pubmed:affiliation
Department of Pediatrics, University of Michigan, Ann Arbor, USA. clchang@ucsd.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't