Identification of a human cDNA encoding a novel Bcl-x isoform.
Alternative splicing has been shown to generate two isoforms of the apoptosis regulator bcl-x, Bcl-xL and Bcl-xS, in humans. Here we describe the identification and characterization of a third splice variant of the human bcl-x gene. It differs from previously described bcl-x transcripts in two respects: (1) a novel facultative intron is spliced out at the 5' untranslated region and (2) the open reading frame arises from a continuous genomic sequence extending over the splice donor sites utilized by the bcl-xL and bcl-xS transcripts. Since the resulting molecule has an organisation homologous to mouse and rat Bcl-x beta we suggest calling this novel protein human Bcl-x beta. Northern blot analysis revealed that bcl-x beta mRNA is expressed in numerous cell lines. Like Bcl-xL, h-Bcl-x binds to the pro-apoptotic protein Bax, suggesting a functional activity in vivo.
Department of Dermatology, University Vienna Medical School, Austria.
J
J
Ban
L
L
Eckhart
W
W
Weninger
M
M
Mildner
E
E
Tschachler
D000595:Amino Acid Sequence; D017209:Apoptosis; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
C494826:BAX protein, human; C494811:BCL2L1 protein, human; D018076:DNA, Complementary; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein