Isolation and structure of a cDNA encoding the B1 (CD20) cell-surface antigen of human B lymphocytes

Journal Article · Fri Jan 01 04:00:00 EST 1988 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

OSTI ID:6271627

Tender, T F; Streuli, M; Schlossman, S F; Saito, H

The B1 (CD20) molecule is a M/sub r/ 33,000 phosphoprotein on the surface of human B lymphocytes that may serve a central role in the homoral immune response by regulating B-cell proliferation and differentiation. In this report, a cDNA clone that encodes the B1 molecule was isolated and the amino acid sequence of B1 was determined. B-cell-specific cDNA clones were selected from a human tonsillar cDNA library by differential hybridization with labeled cDNA derived from either size-fractionated B-cell mRNA or size-fractionated T-cell mRNA. Of the 261 cDNA clones isolated, 3 cross-hybridizing cDNA clones were chosen as potential candidates for encoding B1 based on their selective hybridization to RNA from B1-positive cell lines. The longest clone, pB1-21, contained a 2.8-kilobase insert with an 891-base-pair open reading frame that encodes a protein of 33 kDa. mRNA synthesized from the pB1-21 cDNA clone in vitro was translated into a protein of the same apparent molecular weight as B1. Limited proteinase digestion of the pB1-21 translation product and B1 generated peptides of the same sizes, indicating that the pB1-21 cDNA encodes the B1 molecule. Gel blot analysis indicated that pB1-21 hybridized with two mRNA species of 2.8 and 3.4 kilobases only in B1-positive cell lines. The amino acid sequence deduced from the pB1-21 nucleotide sequence apparently lacks a signal sequence and contains three extensive hydrophobic regions. The deduced B1 amino acid sequence shows no significant homology with other known patients.

• Research Organization: Dana-Farber Cancer Institute, Boston, MA (USA)
• OSTI ID: 6271627
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 85:1; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACID SEQUENCE
ANIMAL CELLS
ANIMALS
ANTIGENS
BIOCHEMISTRY
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CELL DIFFERENTIATION
CELL PROLIFERATION
CHEMISTRY
CONNECTIVE TISSUE CELLS
DNA
DNA SEQUENCING
LEUKOCYTES
LYMPHOCYTES
MAMMALS
MAN
MATERIALS
MOLECULAR STRUCTURE
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
RECOMBINANT DNA
SOMATIC CELLS
STRUCTURAL CHEMICAL ANALYSIS
VERTEBRATES