Protein 4.1R expression in normal and dystrophic skeletal muscle.
4.1R pre-mRNA alternative splicing results in multiple mRNA and protein isoforms that are expressed in virtually all tissues. More specifically, isoforms containing the alternative exon 17a, are exclusively expressed in muscle tissues. In this report, we show that these isoforms are preferentially present in the myoplasm of fast myofibres. 4.1R epitopes are also found at the sarcolemma of both slow and fast myofibres in normal muscle. Interestingly, they are absent from dystrophin-deficient sarcolemma of DMD muscle, and colocalize with partially expressed dystrophin in BMD muscle. We also show that alternative splicing of exons 16 and 17a is regulated during muscle differentiation in an asynchronous fashion, with an early inclusion of exon 16 in forming myotubes, and a late inclusion of exon 17a. Consistently, Western blot analysis led to characterize mainly an approximately 96/98-kDa doublet bearing exons 16-17a-encoding peptide, exclusively occurring in the differentiated muscle.
Delhommeau
François
F
Inserm U473 & Service d'hématologie, hôpital de Bicêtre and faculté de médecine Paris-Sud, 63, rue Gabriel-Péri, 94270 Le Kremlin-Bicêtre cedex, France.
Dalla Venezia
Nicole
N
Morinière
Madeleine
M
Collin
Huguette
H
Maillet
Philippe
P
Guerfali
Ibtissem
I
Leclerc
Philippe
P
Fardeau
Michel
M
Delaunay
Jean
J
Baklouti
Faouzi
F
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D001798:Blood Proteins / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism*; D009136:Muscular Dystrophies / Q000235:genetics* / Q000378:metabolism; D012322:RNA Precursors / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D012322:RNA Precursors; D011994:Recombinant Proteins; C028841:erythrocyte membrane band 4.1 protein