期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2009
卷号：106
期号：24
页码：9703-9708
DOI：10.1073/pnas.0900221106
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：{beta}cyto-Actin and {gamma}cyto-actin are ubiquitous proteins thought to be essential building blocks of the cytoskeleton in all non-muscle cells. Despite this widely held supposition, we show that {gamma}cyto-actin null mice (Actg1-/-) are viable. However, they suffer increased mortality and show progressive hearing loss during adulthood despite compensatory up-regulation of {beta}cyto-actin. The surprising viability and normal hearing of young Actg1-/- mice means that {beta}cyto-actin can likely build all essential non-muscle actin-based cytoskeletal structures including mechanosensory stereocilia of hair cells that are necessary for hearing. Although {gamma}cyto-actin-deficient stereocilia form normally, we found that they cannot maintain the integrity of the stereocilia actin core. In the wild-type, {gamma}cyto-actin localizes along the length of stereocilia but re-distributes to sites of F-actin core disruptions resulting from animal exposure to damaging noise. In Actg1-/- stereocilia similar disruptions are observed even without noise exposure. We conclude that {gamma}cyto-actin is required for reinforcement and long-term stability of F-actin-based structures but is not an essential building block of the developing cytoskeleton.
