A human gene coding for a membrane-associated nucleic acid-binding protein.
Studies to clone a cell-surface DNA-binding protein involved in the binding and internalization of extracellular DNA have led to the isolation of a gene for a membrane-associated nucleic acid-binding protein (MNAB). The full-length cDNA is 4.3 kilobases with an open reading frame of 3576 base pairs encoding a protein of approximately 130 kDa (GenBank accession numbers and ). The MNAB gene is on human chromosome 9 with wide expression in normal tissues and tumor cells. A C3HC4 RING finger and a CCCH zinc finger have been identified in the amino-terminal half of the protein. MNAB bound DNA (K(D) approximately 4 nm) and mutagenesis of a single conserved amino acid in the zinc finger reduced DNA binding by 50%. A potential transmembrane domain exists near the carboxyl terminus. Antibodies against the amino-terminal half of the protein immunoprecipitated a protein of molecular mass approximately 150 kDa and reacted with cell surfaces. The MNAB protein is membrane-associated and primarily localized to the perinuclear space, probably to the endoplasmic reticulum or trans-Golgi network. Characterization of the MNAB protein as a cell-surface DNA-binding protein, critical in binding and internalization of extracellular DNA, awaits confirmation of its localization to cell surfaces.
Departments of Immunology, Pulmonology and Hematology, Veterans Affairs Medical Center, Portland, Oregon 97201, USA.
D C
DC
Siess
C T
CT
Vedder
L S
LS
Merkens
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T
Tanaka
A C
AC
Freed
S L
SL
McCoy
M C
MC
Heinrich
M E
ME
Deffebach
R M
RM
Bennett
S H
SH
Hefeneider
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000737:chemistry; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000378:metabolism; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; D004247:DNA