Multiple isoforms of the tumor suppressor myopodin are simultaneously transcribed in cancer cells.
Expression of myopodin, an actin associated protein, is frequently lost in invasive prostate cancers due to partial or complete deletion of the gene. Screening of public databases reveals that two human myopodin isoforms have been proposed. Remarkably both isoforms deviate profoundly from the human or mouse isoforms examined to date. Here, we investigated expression of human myopodin. Rapid amplification of cDNA ends revealed a new myopodin transcript, hitherto unpredicted by public databases. RT-PCR analysis indicates that the new isoform (Myo2), in addition to the two predicted isoforms (Myo1 and Myo3), are transcribed in various mammalian cell lines. The three isoforms (Myo1-3) are translated into full length proteins of 1093, 1109, and 1261 amino acids, respectively, when expressed in cells. Thus, mammalian cells simultaneously express at least three myopodin isoforms with a common N-terminal PDZ domain, but a dissimilar carboxy-terminal amino acid tract. These findings shed new light on the expression of this tumor suppressor gene and necessitate closer examination of both mouse and human myopodin polypeptides currently under study.
De Ganck
Ariane
A
Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium.
De Corte
Veerle
V
Staes
An
A
Gevaert
Kris
K
Vandekerckhove
Joël
J
Gettemans
Jan
J
D017398:Alternative Splicing; D000818:Animals; D045744:Cell Line, Tumor; D006801:Humans; D051379:Mice; D008840:Microfilament Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D009369:Neoplasms / Q000235:genetics*; D020033:Protein Isoforms / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
D008840:Microfilament Proteins; D020033:Protein Isoforms; C503979:SYNPO2 protein, human; D025521:Tumor Suppressor Proteins