Differential expression of bovine beta-lactoglobulin A and B promoter variants in transiently transfected HC11 cells.
Quantification of beta-lactoglobulin A and B in the milk of heterozygous animals has revealed a differential content of these two variants. Nucleotide sequence analysis of the first 733 bp of the bovine beta-lactoglobulin promoter has indicated the presence of ten polymorphic sites, nine of them being allele A and B specific mutations. To study the differential expression of these alleles, constructs containing 753 bp long fragments of the bovine beta-lactoglobulin A and B associated promoters were used in transient transfection experiments in HC11 cells. A differential transcription activity directed by the A and B specific promoters was consistently observed. The relative expression levels were 57% for beta-lactoglobulin A and 43% for beta-lactoglobulin B promoters. An allele-specific mutation has been reported to have a differential binding affinity to the activator protein-2 between the beta-lactoglobulin A and B promoters. However, experiments in HC11 cells where the activator protein-2 binding sites were mutated in both beta-lactoglobulin A and B promoters showed no major differences in activity between the mutated and native promoters.
Folch
J M
JM
Department of Animal Science, University of California, Davis 95616-8521, USA.
Dovc
P
P
Medrano
J F
JF
D000483:Alleles; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism; D015870:Gene Expression; D007782:Lactoglobulins / Q000235:genetics* / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011401:Promoter Regions, Genetic; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection
D004268:DNA-Binding Proteins; D007782:Lactoglobulins; D050656:Transcription Factor AP-2; D014157:Transcription Factors