title: Dynamic regulation of c-Myc proto-oncogene expression during lymphocyte development revealed by a GFP-c-Myc knock-in mouse.
abstract: c-Myc induces widely varying cellular effects, including cell proliferation and cell death. These different cellular effects are determined, in part, by c-Myc protein expression levels, which are regulated through several transcriptional and post-transcriptional pathways. c-Myc transcripts can be detected in cells at all stages of B and T lymphocyte development. However, little is known about c-Myc protein expression, and how it varies, in developing lymphocytes. Here mice have been generated in which the endogenous c-Myc locus has been modified (c-Myc(G)) so that it encodes a GFP-c-Myc fusion protein. c-Myc(G/G) mice are viable, appear normal and exhibit grossly normal lymphocyte development. Flow cytometric analyses revealed significant heterogeneity in c-Myc protein expression levels in developing c-Myc(G/G) B and T lymphocytes. GFP-c-Myc expression levels were highest in proliferating lymphocytes, suggesting that c-Myc up-regulation is important for promoting lymphocyte cell division, and demonstrating that GFP-c-Myc expression is a marker of proliferating lymphocytes in vivo.
authors.affiliation: Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA.
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Huang
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Bredemeyer
authors.forename: Laura M
authors.initials: LM
authors.lastname: Walker
authors.forename: Craig H
authors.initials: CH
authors.lastname: Bassing
authors.forename: Barry P
authors.initials: BP
authors.lastname: Sleckman
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D049109:Cell Proliferation; D005786:Gene Expression Regulation / Q000276:immunology*; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics*; D037402:Hydrozoa / Q000235:genetics; D008213:Lymphocyte Activation / Q000235:genetics; D016131:Lymphocyte Subsets / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D015514:Oncogene Proteins, Fusion / Q000096:biosynthesis / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D015514:Oncogene Proteins, Fusion; D016271:Proto-Oncogene Proteins c-myc; C485192:green fluorescent protein, Aequorea victoria; D049452:Green Fluorescent Proteins