In vivo monitoring of mRNA movement in Drosophila body wall muscle cells reveals the presence of myofiber domains.
BACKGROUND
In skeletal muscle each muscle cell, commonly called myofiber, is actually a large syncytium containing numerous nuclei. Experiments in fixed myofibers show that mRNAs remain localized around the nuclei in which they are produced.


RESULTS
In this study we generated transgenic flies that allowed us to investigate the movement of mRNAs in body wall myofibers of living Drosophila embryos. We determined the dynamic properties of GFP-tagged mRNAs using in vivo confocal imaging and photobleaching techniques and found that the GFP-tagged mRNAs are not free to move throughout myofibers. The restricted movement indicated that body wall myofibers consist of three domains. The exchange of mRNAs between the domains is relatively slow, but the GFP-tagged mRNAs move rapidly within these domains. One domain is located at the centre of the cell and is surrounded by nuclei while the other two domains are located at either end of the fiber. To move between these domains mRNAs have to travel past centrally located nuclei.


CONCLUSIONS
These data suggest that the domains made visible in our experiments result from prolonged interactions with as yet undefined structures close to the nuclei that prevent GFP-tagged mRNAs from rapidly moving between the domains. This could be of significant importance for the treatment of myopathies using regenerative cell-based therapies.
van Gemert
Alice M C
AM
Laboratory of Gene Expression and Imaging, Department of Molecular Cell Biology, Leiden University Medical C, Leiden, The Netherlands.
van der Laan
Annelies M A
AM
Pilgram
Gonneke S K
GS
Fradkin
Lee G
LG
Noordermeer
Jasprina N
JN
Tanke
Hans J
HJ
Jost
Carolina R
CR
D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D017931:DNA Primers; D004330:Drosophila / Q000196:embryology*; D049452:Green Fluorescent Proteins / Q000235:genetics; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D009132:Muscles / Q000378:metabolism*; D009210:Myofibrils / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins
EMBO J. 2007 Feb 21;26(4):1117-28
17304221
J Cell Sci. 2008 Mar 15;121(Pt 6):887-94
18303053
Nucleic Acids Res. 1987 Dec 23;15(24):10483-93
3697094
Cell. 2004 Mar 5;116(5):683-98
15006351
Muscle Nerve. 1999 Oct;22(10):1350-60
10487900
J Neurosci. 1993 Jan;13(1):144-66
8093713
EMBO J. 2005 Nov 2;24(21):3781-92
16237460
Biochem J. 1990 May 15;268(1):231-6
2188648
Biophys J. 2003 Oct;85(4):2240-52
14507689
Trends Biochem Sci. 2008 Mar;33(3):141-50
18291657
Development. 2007 Mar;134(5):901-8
17267447
Methods Cell Biol. 1994;44:445-87
7707967
Curr Protoc Cell Biol. 2008 Jun;Chapter 4:Unit 4.18
18551421
J Cell Biol. 2006 Jan 2;172(1):9-18
16390995
Dev Biol. 1998 Dec 1;204(1):151-64
9851849
PLoS Genet. 2006 Dec 29;2(12):e180
17196039
Mol Biol Cell. 2004 Oct;15(10):4749-60
15292455
Science. 2005 Sep 2;309(5740):1514-8
16141059
J Cell Biol. 2006 Apr 24;173(2):219-30
16636144
Curr Biol. 2003 Jan 21;13(2):161-167
12546792
Trends Mol Med. 2007 Dec;13(12):520-6
17983835
J Cell Biol. 2001 Sep 17;154(6):1173-83
11551978
Curr Biol. 2006 Jul 25;16(14):1447-52
16860745
Am J Pathol. 2005 Jun;166(6):1741-8
15920159
J Cell Biol. 1992 Dec;119(5):1063-8
1447288
J Neurosci. 2000 Sep 1;20(17):6385-93
10964944
J Cell Biol. 1986 Oct;103(4):1517-25
3095337
Annu Rev Neurosci. 1999;22:389-442
10202544
Neuron. 2001 Jul 19;31(1):15-22
11498047
Mol Cell. 2007 Mar 9;25(5):635-46
17349952
Exp Cell Res. 1997 Nov 1;236(2):453-62
9367630
Methods Enzymol. 2004;375:443-55
14870682
J Cell Biol. 1989 Nov;109(5):2275-88
2681230
Chem Biol. 2006 Jun;13(6):615-23
16793519
Nucleic Acids Res. 1987 Feb 25;15(4):1353-61
3822832
Development. 2000 Oct;127(19):4253-64
10976056
Nat Rev Genet. 2007 Jul;8(7):533-43
17572691
Methods. 2003 Jan;29(1):14-28
12543068
Mol Cell. 1998 Oct;2(4):437-45
9809065
Dev Biol. 2006 Jan 15;289(2):336-45
16337624
Biophys J. 2007 Apr 15;92(8):2694-703
17259280
Mech Dev. 2007 Aug;124(7-8):617-30
17543506
Development. 1993 Jun;118(2):401-15
8223268
Eur J Hum Genet. 1999 Jan;7(1):2-11
10094185
Trends Cell Biol. 2005 Feb;15(2):84-91
15695095
Methods Enzymol. 2004;375:393-414
14870680
Nature. 1989 Feb 9;337(6207):570-3
2915707
Nat Rev Mol Cell Biol. 2005 May;6(5):363-75
15852043
Muscle Nerve. 1998 Jan;21(1):91-103
9427228