Cloning and Functional Analysis of a Family of Nuclear Matrix Transcription Factors (NP/NMP4) that Regulate Type I Collagen Expression in Osteoblasts

Abstract

Collagen expression is coupled to cell structure in connective tissue. We propose that nuclear matrix architectural transcription factors link cell shape with collagen promoter geometry and activity. We previously indicated that nuclear matrix proteins (NP/NMP4) interact with the rat type I collagen ␣1(I) polypeptide chain (COL1A1) promoter at two poly(dT) sequences (sites A and B) and bend the DNA. Here, our objective was to determine whether NP/NMP4-COL1A1 binding influences promoter activity and to clone NP/NMP4. Promoter-reporter constructs containing 3.5 kilobases (kb) of COL1A1 5 flanking sequence were fused to a reporter gene. Mutation of site A or site B increased promoter activity in rat UMR-106 osteoblast-like cells. Several full-length complementary DNAs (cDNAs) were isolated from an expression library using site B as a probe. These clones expressed proteins with molecular weights and COL1A1 binding activity similar to NP/NMP4. Antibodies to these proteins disrupted native NP/NMP4-COL1A1 binding activity. Overexpression of specific clones in UMR-106 cells repressed COL1A1 promoter activity. The isolated cDNAs encode isoforms of Cys 2 His 2 zinc finger proteins that contain an AT-hook, a motif found in architectural transcription factors. Some of these isoforms recently have been identified as Cas-interacting zinc finger proteins (CIZ) that localize to fibroblast focal adhesions and enhance metalloproteinase gene expression. We observed NP/NMP4/CIZ expression in osteocytes, osteoblasts, and chondrocytes in rat bone. We conclude that NP/NMP4/CIZ is a novel family of nuclear matrix transcription factors that may be part of a general mechanical pathway that couples cell structure and function during extracellular matrix remodeling. (J Bone Miner Res 2001;16:10 -23)

Quercetin reversed lipopolysaccharide-induced inhibition of osteoblast differentiation through the mitogen-activated protein kinase pathway in MC3T3-E1 cells

“…Col1, the most abundant and widely distributed type of collagen, is required and sufficient for extracellular matrix mineralization to occur in bone. Col1 is composed of two chains, α1 and α2, encoded by two distinct genes, Col1α1 and Col1α2, which are highly expressed in osteoblasts (22)(23)(24). In the present study, the mRNA expression levels of ALP, Osx, Runx2, Col1α1, OCN and BSP in MC3T3-E1 cells were significantly downregulated by LPS.…”

Prenatal antiepileptic exposure associates with neonatal DNA methylation differences

“…27 COL21A1 is localized to tissues containing type I collagen, and a CpG site in zinc finger protein 384 (ZNF384), which binds and regulates the promoter of type 1 collagen, was also differentially methylated in both umbilical cord blood and placental DNA. This transcription factor is expressed in osteocytes, osteoblasts and chondrocytes 28 and is believed to facilitate their formation through extracellular matrix remodeling. ZNF384 may also bind to numerous genes involved in osteogenesis, hematopoiesis and gonadal development.…”

Nmp4/CIZ Suppresses the Parathyroid Hormone Anabolic Window by Restricting Mesenchymal Stem Cell and Osteoprogenitor Frequency

“…Additionally, Nmp4/CIZ deficiency augmented newly formed trabecular bone mass after femoral BM ablation as compared to WT mice [24], confirming the enhanced osteogenic capacity of the reconstituted KO BM. It is certainly tenable that multiple stem/ progenitor types are necessary for maintaining an open PTH anabolic window, and that one transcription factor has significant direct and/or indirect control over these populations was unexpected despite the fact that Nmp4/CIZ is expressed in multiple cell and tissue types [41]. Nmp4/CIZ has been proposed as a potential target for osteoporosis therapy, [42] and the present data further develop this idea, suggesting that disabling Nmp4/CIZ may provide an adjuvant therapy for extending PTH clinical efficacy by expanding the stem/progenitor populations sustaining its anabolic action.…”