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A (GATA)(7) motif located in the 5' boundary area of the human beta-globin locus control region exhibits silencer activity in erythroid cells. Am J Hematol 2000 Sep;65(1):14-24

Date

08/11/2000

Pubmed ID

10936858

DOI

10.1002/1096-8652(200009)65:1<14::aid-ajh3>3.0.co;2-f

Abstract

A 40-bp DNA, consisting of seven tandem GATA repeats, is located near the HS5 site in the 5' boundary area of the locus control region (LCR) of human beta-globin gene. This (GATA)(7) motif, named 5a, exhibits silencer activity in erythroid cells. In transfected, recombinant plasmids containing the chloramphenicol acetyltransferase (CAT) reporter gene, 5a repressed the activity of the cis-linked housekeeping phosphoglycerate kinase (pgk) promoter; 5a also repressed the activity of the cis-linked HS2 enhancer regardless of whether the CAT gene was driven by the pgk or the epsilon-globin promoter. Repression by 5a was most severe when 5a was spliced upstream of HS2 at a distance of less than 200 bases from the HS2 enhancer core. The silencer activity of 5a was independent of whether the component GATA motifs were in head to tail orientation as in the wild type 5a or in head to head or tail to tail orientation as in a mutant 5a. Band shift experiments show that the GATA-1 protein binds to both 5a and the mutant 5a and forms a large protein complex. Together, the results suggest that GATA-1 bound at 5a is a strong, proximal repressor of HS2 enhancer activity.

Author List

Ramchandran R, Bengra C, Whitney B, Lanclos K, Tuan D

Author

Ramani Ramchandran PhD Professor in the Pediatrics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Base Sequence
Cell Line
Chloramphenicol O-Acetyltransferase
DNA, Recombinant
DNA-Binding Proteins
Enhancer Elements, Genetic
Erythrocytes
Erythroid-Specific DNA-Binding Factors
GATA1 Transcription Factor
Gene Expression
Globins
Humans
Locus Control Region
Molecular Sequence Data
Mutagenesis
Phosphoglycerate Kinase
Plasmids
Promoter Regions, Genetic
Regulatory Sequences, Nucleic Acid
Repressor Proteins
Tandem Repeat Sequences
Transcription Factors
Transfection
jenkins-FCD Prod-484 8aa07fc50b7f6d102f3dda2f4c7056ff84294d1d