| Autor: |
Pranchevicius, Maria Cristina S., Baqui, Munira M. A., Ishikawa-Ankerhold, Hellen C., Lourenço, Elaine V., Leão, Ricardo M., Banzi, Silmara R., dos Santos, Claudia Tavares, Barreira, Maria Cristina R., Espreafico, Enilza M., Larson, Roy E. |
| Zdroj: |
Cell Motility & the Cytoskeleton; 2008, Vol. 65 Issue 6, p441-456, 16p |
| Abstrakt: |
Nuclear actin and nuclear myosins have been implicated in the regulation of gene expression in vertebrate cells. Myosin V is a class of actin-based motor proteins involved in cytoplasmic vesicle transport and anchorage, spindle-pole alignment and mRNA translocation. In this study, myosin-Va, phosphorylated on a conserved serine in the tail domain (phospho-ser1650 MVa), was localized to subnuclear compartments. A monoclonal antibody, 9E6, raised against a peptide corresponding to phosphoserine1650 and flanking regions of the murine myosin Va sequence, was immunoreactive to myosin Va heavy chain in cellular and nuclear extracts of HeLa cells, PC12 cells and B16-F10 melanocytes. Immunofluorescence microscopy with this antibody revealed discrete irregular spots within the nucleoplasm that colocalized with SC35, a splicing factor that earmarks nuclear speckles. Phospho-ser1650 MVa was not detected in other nuclear compartments, such as condensed chromatin, Cajal bodies, gems and perinucleolar caps. Although nucleoli also were not labeled by 9E6 under normal conditions, inhibition of transcription in HeLa cells by actinomycin D caused the redistribution of phospho-ser1650 MVa to nucleoli, as well as separating a fraction of phospho-ser1650 MVa from SC35 into near-neighboring particles. These observations indicate a novel role for myosin Va in nuclear compartmentalization and offer a new lead towards the understanding of actomyosin-based gene regulation. Cell Motil. Cytoskeleton 2008. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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