Rm. Grumbles et al., REGULATION OF THE RAT INTERSTITIAL COLLAGENASE PROMOTER BY IL-1-BETA,C-JUN, AND RAS-DEPENDENT SIGNALING IN GROWTH-PLATE CHONDROCYTES, Journal of cellular biochemistry, 67(1), 1997, pp. 92-102
In an attempt to better define molecular influences on rat interstitia
l collagenase gene expression in cartilage, the promoter function was
characterized using transient transfection assay, electrophoresis mobi
lity shift assay, and genetic analysis in isolated growth plate chondr
ocytes. Data from 5'-flanking deletion and selected mutations suggest
that multiple cis elements in both the proximal and distal regions of
the promoter were important in the regulation of promoter activity. A
proximal tumor response element (TRE) was shown to be necessary for ba
sal and interleukin (IL)-1 beta-inducible reporter gene activity. Cell
s stimulated by IL-1 beta (1 ng/ml; 18 h) had elevated TRE binding act
ivity, and one of the factors involved was identified as the nuclear p
rotein, c-Jun. Indeed, c-Jun directed antisense oligonucleotides reduc
ed rat interstitial collagenase mRNA. A sense oligonucleotide was inef
fective. Regulation of promoter activity was susceptible to Ras-depend
ent signaling as expression of dominant negative mutant of Ras kinase
(pZIP-RasN17) reduced reporter gene activity. in a comparison of proxi
mal promoter reporter plasmid activity between proliferative and hyper
trophic cells, inhibition of Ras-dependent signaling was less effectiv
e in the later cell type. This study suggests that the activation of n
uclear binding proteins that bind TRE may be a common event with IL-1
beta regulation. Moreover, these data suggest that the regulation of r
at interstitial collagenase gene expression combinatorial process and
multiple cis-acting regulatory sites may interact to exert different e
ffects dependent on the stage of chondrocyte differentiation. (C) 1997
Wiley-Liss, Inc.