title: Conservation of histone H2A/H2B intergene regions: a role for the H2B specific element in divergent transcription.
abstract: The organization and function of potential regulatory elements associated with the promoters of chicken H2A and H2B genes pairs have been examined. The intergene regions of six dispersed and divergently-transcribed H2A/H2B gene pairs contain several extremely well conserved and spaced blocks of sequence homology. Adjacent coding regions are on average 342 base-pairs apart. Respective TATA boxes are separated by 180 base-pairs and within this confined region there are four CCAAT boxes and a previously identified 13 base-pair H2B-specific element (H2B-box) which has homology to the octamer motif present in a number of gene promoter/enhancer elements. Transcription of H2A and H2B genes from wild-type and mutant constructs was measured in transient assays by transfection into HeLa cells, and in permanently transformed clonal cell lines. In vitro separation of the two genes at a unique intergenic site significantly decreased transcription of each gene. This suggested that the H2A/H2B gene pairs contained overlapping promoters. Deletion or point mutagenesis of the H2B-specific element decreased the levels of H2B and the H2A transcripts indicating that this sequence is a common regulatory element of both genes in the divergent-pair configeration.
authors.affiliation: Department of Biochemistry, University of Adelaide, South Australia.
authors.forename: R A
authors.initials: RA
authors.lastname: Sturm
authors.forename: S
authors.initials: S
authors.lastname: Dalton
authors.forename: J R
authors.initials: JR
authors.lastname: Wells
mesh_terms: D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D002642:Chick Embryo; D003001:Cloning, Molecular; D005796:Genes; D005809:Genes, Regulator; D006367:HeLa Cells / Q000378:metabolism; D006657:Histones / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D006657:Histones