The oncogenic fusion protein Pax3-FKHR has a greater post-translational stability relative to Pax3 during early myogenesis.
The childhood solid muscle tumor Alveolar Rhabdomyosarcoma (ARMS) is characterized by the t(2;13)(q35;q14) chromosomal translocation, which results in the fusion of two transcription factors important for myogenesis, Pax3 and FKHR (FOX01a). The effects of myogenic differentiation on the stability of FKHR have been well characterized. However, similar studies have yet to be performed on Pax3 or the oncogenic fusion protein Pax3-FKHR. Therefore, we demonstrate in the physiologically relevant mouse primary myoblast system that the expression of Pax3 decreases nearly 95% during the first 24 h of myogenic differentiation. In contrast, there is an aberrant persistence of expression of Pax3-FKHR during this same time period. These differences in protein expression levels do not result from changes on the transcriptional nor the translational level since we observed no concomitant decrease in the levels of Pax3 or Pax3-FKHR mRNA or in the ability of both proteins to be translated. Instead, a pulse-chase analysis determined that Pax3-FKHR has a half-life significantly greater than\ the half-life of wild type Pax3 demonstrating for the first time that Pax3-FKHR has greater post-translational protein stability relative to wild type Pax3 during early myogenic differentiation. Finally, the persistence of expression of Pax3-FKHR prevents the terminal differentiation of primary myoblasts demonstrating a biological consequence of its aberrant expression.
Miller
Patrick J
PJ
Department of Genetics, Louisiana State University Health Sciences Center, 533 Bolivar Street, New Orleans, LA 70112, USA.
Hollenbach
Andrew D
AD
D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008858:Microscopy, Phase-Contrast; D024510:Muscle Development / Q000502:physiology*; D032446:Myoblasts / Q000378:metabolism*; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors / Q000096:biosynthesis*; D046188:Protein Modification, Translational
D015514:Oncogene Proteins, Fusion; D000072041:PAX3 Transcription Factor; C523321:PAX3-FKHR fusion protein, human; D051761:Paired Box Transcription Factors; C068686:Pax3 protein, mouse
Dev Cell. 2003 Jan;4(1):119-29
12530968
J Biol Chem. 2002 Dec 6;277(49):47928-37
12351634
EMBO J. 2003 Mar 3;22(5):1147-57
12606579
Proc Natl Acad Sci U S A. 2003 Sep 30;100(20):11285-90
13679577
Cell. 2004 Apr 16;117(2):225-37
15084260
Cancer Res. 1993 Nov 1;53(21):5108-12
8221646
Nat Genet. 1993 Nov;5(3):230-5
8275086
Development. 1994 Mar;120(3):603-12
8162858
J Cell Biol. 1994 Jun;125(6):1275-87
8207057
Annu Rev Genet. 1994;28:219-36
7893124
J Biol Chem. 1995 May 19;270(20):11719-22
7744814
Development. 1994 Apr;120(4):957-71
7600971
Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):4213-8
8633043
Cell. 1997 Apr 4;89(1):127-38
9094721
Cell. 1997 Apr 4;89(1):139-48
9094722
J Virol. 1998 Jan;72(1):339-48
9420232
Genomics. 1998 Jan 15;47(2):187-99
9479491
Mol Cell Biol. 1999 Jan;19(1):594-601
9858583
Cancer Res. 1999 Apr 1;59(7 Suppl):1711s-1715s
10197585
EMBO J. 1999 Jul 1;18(13):3702-11
10393185
J Biol Chem. 2004 Nov 5;279(45):47311-9
15322110
Curr Opin Struct Biol. 2000 Feb;10(1):110-6
10679470
EMBO J. 2000 Mar 1;19(5):989-96
10698940
Nature. 2000 Apr 13;404(6779):782-7
10783894
J Biol Chem. 2000 Sep 29;275(39):30169-75
10913147
Mol Cell Biol. 2000 Dec;20(24):9138-48
11094066
J Biol Chem. 2000 Nov 17;275(46):36324-33
10960473
J Biol Chem. 2001 Jun 1;276(22):19033-9
11262400
Methods. 2001 Dec;25(4):402-8
11846609
EMBO J. 2002 May 1;21(9):2263-71
11980723
Biochim Biophys Acta. 2002 Apr 12;1574(3):321-8
11997098
Diabetes. 2003 Mar;52(3):642-9
12606503