![]() |
|
|
Vol. 17, Issue 6, 2524-2536, June 2006
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||



*Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan;
Department of Integrated Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; and
Laboratory for Chromatin Dynamics, Center for Developmental Biology, RIKEN, Kobe 650-0047, Japan
Submitted September 26, 2005;
Revised February 15, 2006;
Accepted March 2, 2006
Monitoring Editor: Karsten Weis
Although the Ran GTPase-activating protein RanGAP mainly functions in the cytoplasm, several lines of evidence indicate a nuclear function of RanGAP. We found that Schizosaccharomyces pombe RanGAP, SpRna1, bound the core of histone H3 (H3) and enhanced Clr4-mediated H3-lysine 9 (K9) methylation. This enhancement was not observed for methylation of the H3-tail containing K9 and was independent of SpRna1RanGAP activity, suggesting that SpRna1 itself enhances Clr4-mediated H3-K9 methylation via H3. Although most SpRna1 is in the cytoplasm, some cofractionated with H3. Sprna1ts mutations caused decreases in Swi6 localization and H3-K9 methylation at all three heterochromatic regions of S. pombe. Thus, nuclear SpRna1 seems to be involved in heterochromatin assembly. All core histones bound SpRna1 and inhibited SpRna1RanGAP activity. In contrast, Clr4 abolished the inhibitory effect of H3 on the RanGAP activity of SpRna1 but partially affected the other histones. SpRna1 formed a trimeric complex with H3 and Clr4, suggesting that nuclear SpRna1 is reciprocally regulated by histones, especially H3, and Clr4 on the chromatin to function for higher order chromatin assembly. We also found that SpRna1 formed a stable complex with Xpo1/Crm1 plus Ran-GTP, in the presence of H3.
Address correspondence to: Takeharu Nishimoto ( tnishi{at}molbiol.med.kyushu-u.ac.jp)
This article has been cited by other articles:
![]() |
R. J. Scott, L. V. Cairo, D. W. Van de Vosse, and R. W. Wozniak The nuclear export factor Xpo1p targets Mad1p to kinetochores in yeast J. Cell Biol., January 12, 2009; 184(1): 21 - 29. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Ohba, H. Nishijima, H. Nishitani, and T. Nishimoto Schizosaccharomyces pombe Snf2SR, a novel SNF2 family protein, interacts with Ran GTPase and modulates both RanGEF and RanGAP activities. Genes Cells, June 1, 2008; 13(6): 571 - 582. [Abstract] [Full Text] [PDF] |
||||