Linked common polymorphisms in the gelatinase a promoter are associated with diminished transcriptional response to estrogen and genetic fitness.
Gelatinase A (matrix metalloproteinase-2) plays a prominent role in multiple biologic processes. Prior studies have established critical roles for gelatinase A transcriptional regulation by defined enhancer elements. To determine possible functional single nucleotide polymorphisms within these elements, we determined the single nucleotide polymorphism distribution within 1,665 bp of the gelatinase A 5'-flanking region, using a healthy homogeneous Caucasian study group of 463 individuals. Among the polymorphisms detected, a G --> A transition at bp -1575 was located immediately 5' to a half-palindromic potential estrogen receptor binding site. In estrogen receptor-positive MCF-7 cells the -1575G allele functioned as an enhancer, whereas the -1575A allele reduced transcription activity significantly. Gel shift assays confirmed that the differences in allelic expression affected binding of the estrogen receptor-alpha to this region. Cotransfection experiments with an estrogen receptor-alpha expression vector in MDA-MB-231 cells, which do not constitutively express an estrogen receptor, revealed that estrogen receptor is absolutely required for enhancing activity. Allelic distribution analysis indicated that a previously reported C --> T transition within an Sp1 binding site at -1306 was in linkage disequilibrium with the -1575G --> A transition. Luciferase reporter studies of the linked variant -1575A -1306T allele versus the wild type -1575G -1306C allele demonstrated an additive reduction in estrogen-dependent reporter activity. The frequency of the -1575G --> A transition deviated significantly from the expected Hardy-Weinberg distribution in two independently assembled study populations consisting of healthy adult blood donors and newborns of Caucasian origin, both with a calculated 21% reduction in genetic fitness. Gelatinase A is a known estrogen-responsive gene and the demonstration of a loss of function polymorphism within an operational estrogen receptor binding site associated with a decrease in genetic fitness underscores the biologic significance of promoter polymorphism analyses.
Harendza
Sigrid
S
Department of Medicine, Division of Nephrology, University of Hamburg, Hamburg D-20246, Germany.
Lovett
David H
DH
Panzer
Ulf
U
Lukacs
Zoltan
Z
Kuhnl
Peter
P
Stahl
Rolf A K
RA
D024506:5' Flanking Region / Q000235:genetics; D000328:Adult; D001943:Breast Neoplasms; D047628:Estrogen Receptor alpha; D004967:Estrogens / Q000378:metabolism*; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D020778:Matrix Metalloproteinase 2 / Q000235:genetics* / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic / Q000235:genetics; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D015183:Restriction Mapping; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D014407:Tumor Cells, Cultured
D047628:Estrogen Receptor alpha; D004967:Estrogens; D011960:Receptors, Estrogen; D016329:Sp1 Transcription Factor; D020778:Matrix Metalloproteinase 2