Molecular Biology

Motoring Inside the Nucleus

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Science  29 Feb 2008:
Vol. 319, Issue 5867, pp. 1162
DOI: 10.1126/science.319.5867.1162d

The highly conserved protein actin not only functions as a critical cytoplasmic actor in cell shape and movement, but also, as shown recently, has a nuclear role in regulating gene expression. The frequent companion of cytoplasmic actin is the motor protein myosin; therefore, it is not surprising that a myosin isoform (NM1) can be found in the nucleus. Ye et al. have examined the contributions of nuclear actin and myosin to transcription and find that NM1 and oligomeric (possibly filamentous) actin cooperate in the transcription of ribosomal RNA genes by RNA polymerase I. A series of experiments demonstrated that NM1 adenosine triphosphatase activity was necessary and that the cyclic actin-myosin interaction observed in skeletal muscle was likely to occur in the nucleus as well. The authors suggest that actin and myosin may collaborate in driving RNA polymerase and its target genes together. — BAP

Genes Dev. 22, 322 (2008).

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