The human λ immunoglobulin enhancer is controlled by both positive elements and developmentally regulated negative elements

Michele A. Glozak, Bonnie B. Blomberg

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

We have recently reported the localization of the first transcriptional enhancer in the human lambda (λ) immunoglobulin light chain locus. Enhancer activity was contained on a 1.2 kb SstI fragment, with partial activity retained on a core 111 bp PstI-SstI fragment. This enhancer is located 11.7kb downstream of Cλ7, the most 3' lambda constant region gene. Using a chloramphenicol acetyl transferase (CAT) assay system, we have now determined the boundaries of the complete enhancer and find it is two- to four-fold as active as the core fragment in both pre-B and B cell lines. Interestingly, a larger fragment, containing the complete enhancer as well as 5' and 3' flanking sequences has four- to eight-fold reduced activity when tested in pre-B cell lines, but full activity in B cell lines. This suggests the presence of developmentally regulated negative elements flanking the human λ enhancer which prevent or reduce its activity at a developmentally incorrect time. By using in vivo footprinting we have begun to examine the protein interactions within this enhancer in a more physiologically relevant manner and have identified motifs which are shared with the murine λ enhancers, as well as motifs unique to the human λ enhancer.

Original languageEnglish (US)
Pages (from-to)427-438
Number of pages12
JournalMolecular Immunology
Volume33
Issue number4-5
DOIs
StatePublished - 1996

Keywords

  • Ig enhancer
  • in vivo footprint
  • negative regulation

ASJC Scopus subject areas

  • Molecular Biology
  • Immunology

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