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.
Siess
D C
DC
Departments of Immunology, Pulmonology and Hematology, Veterans Affairs Medical Center, Portland, Oregon 97201, USA.
Vedder
C T
CT
Merkens
L S
LS
Tanaka
T
T
Freed
A C
AC
McCoy
S L
SL
Heinrich
M C
MC
Deffebach
M E
ME
Bennett
R M
RM
Hefeneider
S H
SH
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