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Mammalian protein homologous to VAT‐1 of Torpedo californica: Isolation from Ehrlich ascites tumor cells, biochemical characterization, and organization of its gene
Author(s) -
Hayess Katrin,
Kraft Regine,
Sachsinger Jana,
Janke Jürgen,
Beckmann Georg,
Rohde Klaus,
Jandrig Burkhard,
Benndorf Rainer
Publication year - 1998
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19980601)69:3<304::aid-jcb8>3.0.co;2-v
Subject(s) - biology , microbiology and biotechnology , gene , complementary dna , cdna library , brca2 protein , exon , genetics , mutation , germline mutation
Recently, interest has focused on the human gene encoding the putative protein homologous to VAT‐1, the major protein of the synaptic vesicles of the electric organ of the Pacific electric ray Torpedo californica , after it has been localized on chromosome locus 17q21 in a region encompassing the breast cancer gene BRCA1 . Chromosomal instability in this region is implicated in inherited predisposition for breast and ovarian cancer. Here we describe isolation and biochemical characterization of a mammalian 48 kDa protein homologous to the VAT‐1 protein of Torpedo californica . This VAT‐1 homolog was isolated from a murine breast cancer cell line (Ehrlich ascites tumor) and identified by sequencing of cleavage peptides. The isolated VAT‐1 homolog protein displays an ATPase activity and exists in two isoforms with isoelectric points of 5.7 and 5.8. cDNA was prepared from Ehrlich ascites tumor cells, and the murine VAT‐1 homolog sequence was amplified by polymerase chain reaction and partially sequenced. The known part of the murine and the human translated sequences share 97% identity. By Northern blots, the size of the VAT‐1 homolog mRNA in both murine and human (T47D) breast cancer cells was determined to be 2.8 kb. Based on the presented data, a modified gene structure of the human VAT‐1 homolog with an extended exon 1 is proposed. VAT‐1 and the mammalian VAT‐1 homolog form a subgroup within the protein superfamily of medium‐chain dehydrogenases/reductases. J. Cell. Biochem. 69:304–315, 1998. © 1998 Wiley‐Liss, Inc.