MOLECULAR-CLONING OF HEK, THE GENE ENCODING A RECEPTOR TYROSINE KINASE EXPRESSED BY HUMAN LYMPHOID TUMOR-CELL LINES
Details
Publication Year 1992-03-01,Volume 89,Issue #5,Page 1611-1615
Journal Title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Publication Type
Journal Article
Abstract
We describe the molecular cloning of a receptor tyrosine kinase from a cell line (LK63) derived from a case of human pre-B-cell leukemia. We have previously shown that a monoclonal antibody (IIIA4) raised against LK63 recognized a glycosylated, cell-surface 135-kDa molecule (HEK), which displayed tyrosine kinase activity in vitro. The HEK protein was purified by using a IIIA4 antibody column and both N-terminal and internal amino acid sequences were obtained. A 51-mer degenerate oligonucleotide based on the internal amino acid sequence was used to screen an LK63-derived lambda-gt1O cDNA library under low-stringency hybridization conditions. One clone of 2.5 kilobases (kb) was isolated and characterized and used to rescreen the library under more-stringent hybridization conditions. A 4.5-kb clone containing the entire HEK coding region was isolated and its complete DNA sequence was determined. The 4.5-kb insert was subcloned into the expression vector CDM8 and transfected into COS cells. COS cells transfected with the sense HEK/CDM8 construct stained specifically with the IIIA4 antibody, thereby confirming that the antigen recognized by the IIIA4 antibody and the expressed protein product of the HEK cDNA clone were identical. DNA sequence analysis revealed that HEK is a newly discovered member of the EPH/ELK family of receptor tyrosine kinases. Northern blot analysis of a number of cell lines demonstrated the expression of 5.5- to 6.0-kb HEK transcripts in LK63 and the T-cell lines JM and HSB-2. Southern blot analysis of DNA from LK63 suggested that the HEK gene was neither amplified nor rearranged in the LK63 tumor.
Publisher
NATL ACAD PRESS
Keywords
SIGNAL TRANSDUCTION; PROTEIN-KINASE; GROWTH-FACTOR; EPH GENE; CDNA; ANTIGEN; FAMILY; DNA
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Creation Date: 1992-03-01 12:00:00
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