Binding of a CTF/NF1-Like Protein to the Mouse Colony-Stimulating Factor-1 Gene Promoter

Abstract

Circulating and tissue-specific monocytes/macrophages, through production of hydrolytic enzymes and growth factors, can dramatically affect the local tissue environment. Colony-stimulating factor-1 (CSF-1) is a key regulator of monocyte/macrophage cell activity. CSF-1 is produced by stromal elements, including fibroblasts, which are found in all tissues. To understand at the molecular level how changes in CSF-1 gene transcription are initiated in fibroblasts, we set out to identify the cis-acting elements and cognate trans-acting factor(s) that bind regulatory regions of the mouse CSF-1 gene. Analysis of heterologous reporter constructs containing the mouse CSF-1 promoter linked to the bacterial chloramphenicol acetyltransferase (CAT) gene in transiently transfected fibroblasts identified a cis-acting element located between base pairs -88 and -43 of the CSF-1 gene. Electrophoretic mobility-shift assays (EMSAs) and DNase I protection assays with nuclear extracts isolated from proliferating fibroblasts revealed distinct protein binding to the region spanning base pairs -90 to -68. Results from methylation interference assays suggest CTF/NF1 or a CTF/NF1-like factor is the cognate trans-acting factor. Mutation of the putative CTF/NF1 binding site in the CSF-1 promoter lead to a modest decrease in promoter activity in transiently transfected fibroblasts and monocytes. Therefore, we have demonstrated that CTF/NF1 or a CTF/NF1-like protein binds to the CSF-1 gene promoter; however, binding of the CTF/NF1-like protein alone does not significantly effect changes in CSF-1 gene promoter activity.

Sex chromosome transformation and the origin of a male-specific X chromosome in the creeping vole

“…7). Mutations in CTF/NF1 binding sites have been shown to decrease transcriptional activity in other promoters (39,40). Most notably, we found an A>G mutation at the transcription initiation site in conserved element I, only present in the X M Xist allele (Fig.…”

Nuclear Factor I-C Links Platelet-Derived Growth Factor and Transforming Growth Factor β1 Signaling to Skin Wound Healing Progression

“…Genes implicated in fibrosis and ECM remodeling were also included, such as Wisp2, a member of the WNT/␤-catenin pathway, Pdgfr␣, one of the PDGF receptors, and Ahr, a ligand-activated transcriptional factor (6,7,9). Finally, Csf1 was also included, due to the identification of an NFI-C binding site in its promoter (27). Transcripts were extracted from four matched pairs of embryonic fibroblasts obtained from NFI-C knockout mice and their respective wild-type littermate controls.…”

Transcriptional regulation of the mouse CSF-1 gene

“…When the mutated CTF/NF1 site was introduced into a truncated CSF-1 reporter constructs (nts 2100 to 1183), there was still no effect on CSF-1 reporter construct activity. At this point, we concluded that the activity of CSF-1 reporter constructs spanning nts 288 to 1183 is the result of proteins binding to the serum-induced element located in the region between nts 262 and 254 and/or to the 2 GC boxes located in the region between nts 243 and 228 (Konicek et al, 1995). Studies to confirm this are ongoing in our lab.…”

“…Data are presented as the average positive standard deviation of duplicated samples from 3 separate transfections. (Reproduced, with permission, fromKonicek et al, 1995).…”

“…Based upon the migration of size markers, the corresponding region of the CSF-1 gene was identified; the numbers indicate position in nucleotides relative to the transcriptional start point. (Reproduced, with permission, fromKonicek et al, 1995).…”