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Profilin I Is Essential for Cell Survival and Cell Division in Early Mouse Development
Walter Witke, James D. Sutherland, Arlene Sharpe, Maya Arai and David J. Kwiatkowski
Proceedings of the National Academy of Sciences of the United States of America
Vol. 98, No. 7 (Mar. 27, 2001), pp. 3832-3836
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/3055329
Page Count: 5
You can always find the topics here!Topics: Profilins, Embryos, Actins, Alleles, Neurons, Cell lines, Blastocyst, Ligands, Antibodies, Protein isoforms
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Profilins are thought to play a central role in the regulation of de novo actin assembly by preventing spontaneous actin polymerization through the binding of actin monomers, and the adding of monomeric actin to the barbed actin-filament ends. Other cellular functions of profilin in membrane trafficking and lipid based signaling are also likely. Binding of profilins to signaling molecules such as Arp2/3 complex, Mena, VASP, N-WASP, dynamin I, and others, further implicates profilin and actin as regulators of diverse motile activities. In mouse, two profilins are expressed from two distinct genes. Profilin I is expressed at high levels in all tissues and throughout development, whereas profilin II is expressed in neuronal cells. To examine the function of profilin I in vivo, we generated a null profilin I (pfn1ko) allele in mice. Homozygous pfn1ko/ko mice are not viable. pfn1ko/ko embryos died as early as the two-cell stage, and no pfn1ko/ko blastocysts were detectable. Adult pfn1ko/wt mice show a 50% reduction in profilin I expression with no apparent impairment of cell function. However, pfn1ko/wt embryos have reduced survival during embryogenesis compared with wild type. Although weakly expressed in early embryos, profilin II cannot compensate for lack of profilin I. Our results indicate that mouse profilin I is an essential protein that has dosage-dependent effects on cell division and survival during embryogenesis.
Proceedings of the National Academy of Sciences of the United States of America © 2001 National Academy of Sciences