Transcriptional regulation of the neuronal L-type XXXX channel alpha 1D subunit gene.

@entity19 @entity11 @entity5015 @entity460 @entity1014 @entity35 @entity1968
1. The transcriptional regulation of the @entity35 brain L-type @entity460 channel alpha 1D subunit (RB alpha 1D) gene was investigated using @entity19 @entity11 cells. 2. Differentiation of @entity19 cells in the presence of @entity5015 or @entity1968 resulted in the appearance of mRNA encoding the RB alpha 1D subunit detected using Northern blot analysis. 3. A @entity35 genomic DNA library was screened, and a 15.2-kb clone was isolated and partially sequenced which included part of the 5' upstream sequence through the initial part of intron 2 of the RB alpha 1D gene. 4. Deletion analysis, using a CAT reporter gene and transfected @entity19 cells, revealed that the 1.2-kb 5'-upstream sequence from the RB alpha 1D gene contains cis-acting positive and negative regulatory elements. A deletion of the 3' end of exon 1 also suggested the presence of regulatory elements in the first exon. 5. DNase footprinting of exon 1 of the RB alpha 1D gene revealed two regions protected from digestion by specific protein binding, and the second region included an (ATG)7 trinucleotide repeat sequence. Electrophoretic mobility shift assays confirmed nuclear protein(s) binding to the (ATG)7 sequence. 6. The (ATG)7 sequence functions as a enhancer when linked to a @entity1014 kinase promoter and a CAT reporter gene. 7. These results provide the initial description of the transcriptional regulation of the RB alpha 1D gene and identify a novel enhancer that consists of an (ATG)7 trinucleotide repeat sequence.
