Structure, chromosomal localization, and methylation pattern of the human mb-1 gene
- Univ. of Alabama, Birmingham, AL (United States)
- Children's Hospital, Philadelphia, PA (United States)
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, the authors 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 TAT 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[prime] 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[prime] region of the gene and expression of mb-1. The demethylated Hpall/Mspl 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. 59 refs., 6 figs., 1 tab.
- OSTI ID:
- 6965133
- Journal Information:
- Journal of Immunology; (United States), Vol. 152:12; ISSN 0022-1767
- Country of Publication:
- United States
- Language:
- English
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HUMAN CHROMOSOME 19
GENETIC MAPPING
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GENES
MEMBRANE PROTEINS
RECEPTORS
DNA HYBRIDIZATION
POLYMERASE CHAIN REACTION
ANIMAL CELLS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CHROMOSOMES
CONNECTIVE TISSUE CELLS
GENE AMPLIFICATION
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550400* - Genetics