Actin in the Cell Nucleus

In the cell nucleus, actin is a component of chromatin-remodeling complexes and is associated with the mammalian genome. Across active genes, nuclear actin binds all eukaryotic RNA polymerases and it is incorporated into precursor and mature ribonucleoprotein complexes. As in the cytoplasm, nuclear actin undergoes regulated changes in its polymerization state and these changes have been linked to chromosome dynamics and, more recently, to DNA repair. Here, we summarize some of the recent findings that support the general importance of actin in the functional architecture of the cell nucleus at both gene and genomic levels. Furthermore, we discuss how nuclear actin, in conjunction with certain actin-binding proteins such as myosin, globally impacts gene expression and can potentially contribute to genome integrity.