Structure, chromosomal localization, and methylation pattern of the human mb-1 gene.

Academic Article

Abstract

  • The Ag receptor on B lymphocytes is a multimeric complex that is composed of an Ag-specific component, surface Ig, which is noncovalently associated with at least two other proteins, Ig alpha and Ig beta. These are the glycoprotein products of the B lineage-restricted mb-1 and B29 genes and are crucial for the cell surface expression and function of the Ag receptor on B lymphocytes. To better understand the regulation of mb-1, we have cloned and sequenced a 5.7-kb genomic DNA fragment that contained the human gene. The overall structure of human mb-1 is very similar to that of the murine gene, including the number and approximate size of exons. The promoter region lacks a TATA element, but contains two copies of an early B cell factor-binding motif, which previously has been shown to be important for murine mb-1 expression. Other structural features include two nuclear factor-kappa B binding sites at the 5' end of the gene and a long stretch of AG rich-sequence between exons 3 and 4, downstream of an Alu repeat sequence that contains a potential stem-loop structure. The mb-1 gene was localized to chromosome 19q13.2-13.3 by a combination of two methods, PCR amplification of DNA from a somatic cell hybrid-mapping panel and fluorescence in situ hybridization. An examination of the methylation pattern revealed a striking correlation between demethylation in the 5' region of the gene and expression of mb-1. The demethylated HpaII/MspI sites are adjacent to the nuclear factor-kappa B-binding motifs, which suggests a role for this transcription factor in the regulation of human mb-1 gene expression.
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    Published In

    Keywords

  • Amino Acid Sequence, Animals, Antigens, CD, Base Sequence, CD79 Antigens, Chromosome Mapping, Chromosomes, Human, Pair 19, DNA, DNA Primers, Genes, Regulator, Humans, Male, Membrane Glycoproteins, Methylation, Mice, Molecular Sequence Data, Molecular Structure, NF-kappa B, Promoter Regions, Genetic, Receptors, Antigen, B-Cell, Sequence Homology, Nucleic Acid, Species Specificity, Transcription, Genetic
  • Author List

  • Ha H; Barnoski BL; Sun L; Emanuel BS; Burrows PD
  • Start Page

  • 5749
  • End Page

  • 5757
  • Volume

  • 152
  • Issue

  • 12