title: Expression of Krox proteins during differentiation of the O-2A progenitor cell line CG-4.
abstract: Krox proteins are important regulators of development and terminal differentiation. Using the rat glial progenitor cell line CG-4 as a model system for oligodendrocyte differentiation, we show that on the RNA level Krox-24 is the predominant member of the Krox family in these cells. Similar results were also obtained on the protein level as the major Krox protein from CG-4 cell extracts reacted specifically with an antibody against Krox-24. Whereas Krox-24 RNA and protein were abundant in undifferentiated CG-4 cells, a dramatic decrease in expression was detected after a 3-5-day period of differentiation during which we observed a reciprocal increase in the levels of myelin basic protein expression. Importantly, regulation of Krox-24 expression was very similar in CG-4 cells and primary oligodendrocyte cultures. When expression of Krox-24 in differentiating CG-4 cells was followed on a closer time scale, we observed a sharp and transient increase in Krox-24 RNA, protein, and DNA binding activity immediately after the onset of differentiation followed by an equally rapid decrease. This expression pattern implicates Krox-24 both in maintenance of the undifferentiated state and in the immediate early phase of differentiation of CG-4 cells and possibly oligodendrocytes.
authors.affiliation: Zentrum für Molekulare Neurobiologie, Universität Hamburg, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Sock
authors.forename: H
authors.initials: H
authors.lastname: Leger
authors.forename: K
authors.initials: K
authors.lastname: Kuhlbrodt
authors.forename: J
authors.initials: J
authors.lastname: Schreiber
authors.forename: J
authors.initials: J
authors.lastname: Enderich
authors.forename: C
authors.initials: C
authors.lastname: Richter-Landsberg
authors.forename: M
authors.initials: M
authors.lastname: Wegner
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D051767:Early Growth Response Protein 2; D017874:Immediate-Early Proteins; D051379:Mice; D009457:Neuroglia / Q000166:cytology* / Q000378:metabolism*; D009836:Oligodendroglia / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; D051767:Early Growth Response Protein 2; C486109:Egr1 protein, mouse; C486110:Egr1 protein, rat; C497327:Egr2 protein, mouse; C497328:Egr2 protein, rat; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D014157:Transcription Factors