A 3' transcriptional enhancer regulates tissue-specific expression of the human CD2 gene.
A strong lymphocyte-specific transcriptional enhancer was identified within a DNase I hypersensitive site at the 3' end of the human CD2 gene. Full activity, in a transient expression assay, was contained within a region of 550 bp (minimal enhancer). T cells which express CD2 could use the enhancer to activate transcription from the reporter gene chloramphenicol acetyltransferase in the context of a heterologous promoter. Lower levels of transcription were detected in non-CD2-expressing T cells and in B cells. In contrast, the enhancer did not function in the epithelial cell line HeLa or in Colo 320 HSR, a cell line of neuroendocrine origin. Low levels of enhancement were detectable from two core regions, which acted synergistically with other cis-acting sequences to generate the complete enhancer. DNase I footprinting studies identified six cis-acting sequences to which proteins bound. Five of these sequence motifs were novel; the sixth was a canonical cAMP response element. Topoisomerase II, and scaffold attachment region consensus sequences were also found within an A/T-rich area downstream of the minimal enhancer. Neither region was bound to the nuclear matrix. The CD2 enhancer is modular in structure, it is constructed of novel cis-acting sequences and it is a major component of the regulatory system that controls expression of the CD2 gene.
Imperial Cancer Research Fund, St Bartholomew's Hospital, London, UK.
R A
RA
Lake
D
D
Wotton
M J
MJ
Owen
D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D015342:DNA Probes; D003850:Deoxyribonuclease I; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015183:Restriction Mapping; D014158:Transcription, Genetic; D014162:Transfection
D015342:DNA Probes; D011993:Recombinant Fusion Proteins; D015500:Chloramphenicol O-Acetyltransferase; D003850:Deoxyribonuclease I