ISSN:
0730-2312
Keywords:
Lysyl oxidase
;
type I collagen
;
myofibroblast
;
fibrosis
;
mRNA
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Lysyl oxidase (LO), an extracellular enzyme catalysing the first step of collagen and elastin cross-linking, is transiently expressed by myofibroblasts during fibrosis. A cell model with features of myofibroblast was thus established for studying the regulation of LO. Two clones of the 3T6 fibroblast cell line were selected because 1) they produced a relatively high steady-state level of the three lysyl oxidase mRNAs with the same relative ratio similar to fibrotic tissue and 2) they stably displayed certain features of myofibroblast (α-smooth muscle actin cytoskeleton, bundles of cytoskeletal filaments beneath the cytoplasmic membranes). These clones synthesized predominantly type I collagen fibers and a small amount of type III collagen. Neither type IV collagen nor elastin were observed. The cloning and sequencing of 2,073 bp of the mouse Balb/C LO promoter was performed, allowing the identification around the initiation of transcription of consensus sequences which are found on the COL1 promoters. A series of deletion constructs containing the LO 5′-flanking region ligated to the luciferase gene were transiently transfected into 3T6-5 fibroblasts. The region allowing the maximal activity was found between positions -416 to -192, while the more upstream region negatively regulated the promoter. The -898 to -865 sequence (called LOcol1) displayed 79% of homology with a conserved sequence of murine, rat, and human COL1A1 promoters. This sequence participated to the binding of several nuclear factors within a region (-970 to -784) allowing 50% of inhibition of the LO promoter. Therefore, the level of LO transcription is regulated in 3T6-5 fibroblast by positive and negative cis-acting regulatory elements which might have common features with the COL1A1 promoter. J. Cell. Biochem. 64:328-341.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
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