A chimeric gene was constructed by fusing the DNA sequences containing the 5' flanking region of the mouse al(III) collagen gene to the coding sequence of the bacterial chioramphenicol acetyltransferase (CAT) gene. Transient transfection experiments indicated that the al(III) promoter is active in NIH 3T3 fibroblasts and BC3Hl smooth muscle cells. The activity of the al(III) collagen promoter-CAT plasmid is stimulated approximately ten fold by the presence of the SV40 enhancer element. Removing sequences upstream of -200 stimulates the activity of the chimeric gene eight fold. Further deletion analysis identified sequences located between -350 and -300 that were instrumental in repressing the activity of the promoter. This 50 bp region contains a direct repeat sequence that may be involved in the regulation of the mouse al(III) collagen gene. Truncating the al(III) promoter to -80 further stimulated expression. We propose that the positive regulatory elements of this gene appear to be located within the first 80 bp of the promoter, whereas elements located further upstream exert a negative effect on the expression of the gene. Regulation of the al(III) gene contrasts with that of the a2(I) collagen gene, which appears to be regulated by several positive elements located in various regions of the promoter.
ASJC Scopus subject areas
- Statistics, Probability and Uncertainty
- Applied Mathematics
- Health, Toxicology and Mutagenesis