Identification of an alternatively spliced seprase mRNA that encodes a novel intracellular isoform.
Seprase is a homodimeric 170-kDa integral membrane gelatinase that is related to the ectoenzyme dipeptidyl peptidase IV. We have identified an alternatively spliced seprase messenger from the human melanoma cell line LOX that encodes a novel truncated isoform, seprase-s. The splice variant mRNA is generated by an out-of-frame deletion of a 1223-base pair exonic region that encodes part of the cytoplasmic tail, transmembrane, and the membrane proximal-central regions of the extracellular domain (Val(5) through Ser(412)) of the seprase 97-kDa subunit (seprase-l). The seprase-s mRNA has an elongated 5' leader (548 nucleotides) that harbors at least two upstream open reading frames that inhibit seprase-s expression from a downstream major open reading frame. Deletion mutagenesis of the wild type splice variant cDNA confirms that initiation of the seprase-s coding sequence begins with an ATG codon that corresponds to Met(522) of seprase-l. The seprase-s open reading frame encodes a 239-amino acid polypeptide with an M(r) approximately 27,000 that precisely overlaps the carboxyl-terminal catalytic region of seprase-l.
Goldstein
L A
LA
Department of Medicine, Division of Medical Oncology, State University of New York, Stony Brook, New York 11794-8160, USA.
Chen
W T
WT
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D003001:Cloning, Molecular; D018076:DNA, Complementary; D010450:Endopeptidases; D018093:Gelatinases / Q000235:genetics*; D006801:Humans; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016366:Open Reading Frames; D020033:Protein Isoforms / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D012697:Serine Endopeptidases; D014407:Tumor Cells, Cultured; D000099167:Fibroblast Activation Protein Alpha
D018076:DNA, Complementary; D010450:Endopeptidases; D018093:Gelatinases; D008565:Membrane Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D012697:Serine Endopeptidases; D000099167:Fibroblast Activation Protein Alpha