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Updated: Jul 20, 2026

Myosin-Specific Adaptations of In vitro Fluorescence Microscopy-Based Motility Assays
Published on: February 4, 2021
From transcription to transport: emerging roles for nuclear myosin I
Wilma A Hofmann1, Terezina Johnson, Marcin Klapczynski
1Department of Physiology and Biophysics, University of IL at Chicago, 835 S. Wolcott, Chicago, IL 60612, USA.
Abstract:
Myosins are a superfamily of actin-activated ATPases that, in the cytoplasm, work together with actin as molecular motors. The presence of actin in the nucleus has been known for many years. The demonstration of a nuclear isoform of a myosin, nuclear myosin I (NMI), stimulated a great deal of interest in possible intranuclear motor functions of an acto-NMI complex. NMI has been shown to be involved in transcription by RNA polymerases I and II. In both cases, NMI interacts with the respective polymerase and is critically involved in the basic process of transcription. A recent study on intranuclear long-range chromosome movement has now demonstrated a role for NMI in the translocation of chromosome regions as well. Moreover, this movement is based on an active and directed process that is facilitated by an acto-NMI complex, establishing for the first time a functional role for a motor complex consisting of actin and a myosin in the nucleus.
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