title: Identification of factors mediating the developmental regulation of the early acting -3.9 kb chicken lysozyme enhancer element.
abstract: The chicken lysozyme gene -3.9 kb enhancer forms a DNase I hypersensitive site (DHS) early in macrophage differentiation, but not in more primitive multipotent myeloid precursor cells. A nucleosome becomes precisely positioned across the enhancer in parallel with DHS formation. In transfection assays, the 5'-part of the -3.9 kb element has ubiquitous enhancer activity. The 3'-part has no stimulatory activity, but is necessary for enhancer repression in lysozyme non-expressing cells. Recent studies have shown that the chromatin fine structure of this region is affected by inhibition of histone deacetylase activity after Trichostatin A (TSA) treatment, but only in lysozyme non-expressing cells. These results indicated a developmental modification of chromatin structure from a dynamic, but inactive, to a stabilised, possibly hyperacetylated, active state. Here we have identified positively and negatively acting transcription factors binding to the -3.9 kb enhancer and determined their contribution to enhancer activity. Furthermore, we examined the influence of TSA treatment on enhancer activity in macrophage cells and lysozyme non-expressing cells, including multipotent macrophage precursors. Interestingly, TSA treatment was able to restore enhancer activity fully in macrophage precursor cells, but not in non-macrophage lineage cells. These results suggest (i) that the transcription factor complement of multipotent progenitor cells is similar to that of lysozyme-expressing cells and (ii) that developmental regulation of the -3.9 kb enhancer is mediated by the interplay of repressing and activating factors that respond to or initiate changes in the chromatin acetylation state.
authors.affiliation: Molecular Medicine Unit, University of Leeds, St James's University Hospital, Clinical Sciences Building, Leeds LS9 7TF, UK.
authors.forename: P
authors.initials: P
authors.lastname: Lefevre
authors.forename: J
authors.initials: J
authors.lastname: Kontaraki
authors.forename: C
authors.initials: C
authors.lastname: Bonifer
mesh_terms: D020856:AT Rich Sequence / Q000235:genetics; D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive; D002454:Cell Differentiation / Q000235:genetics; D002461:Cell Line, Transformed; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D018983:DNA Footprinting; D024202:Electrophoretic Mobility Shift Assay; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006410:Hematopoiesis / Q000235:genetics; D051548:Histone Acetyltransferases; D006877:Hydroxamic Acids / Q000494:pharmacology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D009113:Muramidase / Q000235:genetics*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D006877:Hydroxamic Acids; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C012589:trichostatin A; D004247:DNA; D008156:Luciferases; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; D009113:Muramidase; D001616:beta-Galactosidase