title: Expression of FosB during mouse development: normal development of FosB knockout mice.
abstract: FosB, one of the members of the Fos family, is rapidly induced in many cell types upon stimulation and has a stimulatory effect on the proliferation of cultured cells. To understand the tissue distribution of FosB, we have studied its expression pattern by immunohistochemistry in newborn and late embryonic stage mice. These results show that FosB is widely expressed with the highest levels of expression observed in both bony and cartilagenous regions of developing bone. FosB is also detected within whisker follicles, liver, and epidermal tissue. To study the role of FosB in mammalian development we generated embryonic stem (ES) cells, mice and mouse embryo fibroblasts (MEFs) that are deficient for FosB. FosB -/- mice are born at a normal frequency, are fertile and present no obvious phenotypic or histologic abnormalities. FosB-deficient ES cells and MEFs proliferate and enter the S phase normally and we do not find upregulation of other fos family genes to compensate for the lack of FosB. However, we do find that the induction of two AP-1 containing genes is reduced after stimulation of FosB-deficient cells, demonstrating that FosB does indeed play a functional role in transcriptional regulation.
authors.affiliation: Bristol-Meyers Squibb Pharmaceutical Research Institute, Department of Oncology, Princeton, New Jersey 08543-4000, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Gruda
authors.forename: J
authors.initials: J
authors.lastname: van Amsterdam
authors.forename: C A
authors.initials: CA
authors.lastname: Rizzo
authors.forename: S K
authors.initials: SK
authors.lastname: Durham
authors.forename: S
authors.initials: S
authors.lastname: Lira
authors.forename: R
authors.initials: R
authors.lastname: Bravo
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000196:embryology; D002453:Cell Cycle / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D004848:Epithelium / Q000196:embryology; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D016762:Genes, fos; D007150:Immunohistochemistry; D008099:Liver / Q000196:embryology; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D013234:Stem Cells / Q000166:cytology / Q000502:physiology; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism
chemical_list: D018808:Transcription Factor AP-1