title: Role of positive and negative cis-regulatory elements in the transcriptional activation of the lysozyme locus in developing macrophages of transgenic mice.
abstract: Expression of the chicken lysozyme locus in macrophages is regulated by at least six different positive and negative cis-regulatory elements. Chromatin of the chicken lysozyme locus is gradually reorganized during macrophage differentiation, indicating that each cis-regulatory element is activated at a different developmental stage. Irrespective of their differential developmental activation, individual cis-regulatory regions are capable of driving transcription of the lysozyme gene in mature macrophages of transgenic mice. In order to examine the role of different cis-regulatory regions in lysozyme locus activation, we analyzed the time course of transcriptional up-regulation of deletion mutants of the lysozyme locus in a new in vitro differentiation system based on enriched primary macrophage precursor cells from the bone marrow of transgenic mice. We show that constructs carrying cis-regulatory elements which are structurally reorganized early in development are also transcriptionally active at an early stage. A construct in which the early enhancer has been deleted shows a delay in transcriptional activation. The presence or absence of a negative regulatory element has no influence on the time course of transcriptional activation of the lysozyme locus.
authors.affiliation: Institut für Biologie III der Universität Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Federal Republic of Germany.
authors.forename: U
authors.initials: U
authors.lastname: Jägle
authors.forename: A M
authors.initials: AM
authors.lastname: Müller
authors.forename: H
authors.initials: H
authors.lastname: Kohler
authors.forename: C
authors.initials: C
authors.lastname: Bonifer
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002645:Chickens; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D007377:Interleukin-3 / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism; D008264:Macrophages / Q000201:enzymology; D051379:Mice; D008822:Mice, Transgenic; D009113:Muramidase / Q000235:genetics*; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D007377:Interleukin-3; D012333:RNA, Messenger; D014157:Transcription Factors; D016173:Macrophage Colony-Stimulating Factor; D007041:Hypoxanthine Phosphoribosyltransferase; D009113:Muramidase