Alternative polyadenylation produces two major transcripts of Alix.
The mammalian adaptor protein Alix participates in multiple cellular processes. Since mouse Alix cDNA detects two distinct transcripts of approximately 3.5 and approximately 7.0 kb in various mouse tissues, it is possible that there exist isoforms of Alix protein that perform varied biological functions. In this study, we first demonstrate that four different anti-Alix monoclonal antibodies immunoblot the single Alix protein in nine different mouse tissues. We then show that the two transcripts of 3.2 and 6.4 kb are widely expressed in various human tissues and cell lines. These two transcripts are generated from the same Alix gene localizing at 3p22.3 via alternative polyadenylation, thus containing an identical open reading frame. However, the 3.2-kb transcript is much more active in translation than the 6.4-kb transcript in a randomly selected cell line. These results eliminate the possibility that the two transcript variants encode different isoforms of Alix protein and suggest that alternative polyadenylation is one of the mechanisms controlling Alix protein expression.
Department of Experimental Therapeutics, The University of Texas M. D., Anderson Cancer Center, Box 019, 1515 Holcombe blvd., Houston, TX 77030, USA.
Zhehui
Z
Feng
Chuan Fen
CF
Wu
Xi
X
Zhou
Jian
J
Kuang
D000595:Amino Acid Sequence; D000818:Animals; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D026723:Polyadenylation / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D056827:Endosomal Sorting Complexes Required for Transport; C117020:PDCD6IP protein, human; C492144:Pdcd6ip protein, mouse; D014157:Transcription Factors