A Novel Function of Plant Histone H1: Microtubule Nucleation and Continuous Plus End Association

Cell Structure and Function

Koichi Mizuno¹  Tokuko Haraguchi²  Takashi Hotta¹ 

[1] Department of Biological Sciences, Graduate School of Science, Osaka University;Cell Biology Group, Kansai Advanced Research Center, National Institute of Information and Communications Technology

关键词: histone H1;    nucler surface;    microtubule-organizing center;    radial microtubules;    tobacco BY-2 cells;   

DOI  :  10.1247/csf.07031

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(41)Cited-By(10)In higher plant cells, various microtubular arrays can be seen despite of their lack of structurally defined microtubule-organizing centers (MTOCs) like centrosomes in animal cells. Little is known about the molecular properties of the microtubule-organizing centers in higher plant cells. The nuclear surface contains one of these microtubule-organizing centers and generates microtubules radially toward the cell periphery (radial microtubules). Previously, we reported that histone H1 possessed the microtubule-organizing activity, and it was suggested that histone H1 localized on the nuclear surfaces in Tobacco BY-2 cells (Nakayama, T., Ishii, T., Hotta, T., and Mizuno, K. J. Biol. Chem. (submitted)). Here we show that histone H1 forms ring-shaped complexes with tubulin, and these complexes nucleated and elongated the radial microtubules continuously (processively) associating with their proximal ends where the incorporation of tubulin occurred. Furthermore, the polarity of radial microtubules was determined to be proximal end plus. Immunofluorescence microscopy of the isolated nuclei revealed that histone H1 localized on the nuclear surfaces, distinct from that in the chromatin. These results indicate that radial microtubules are organized by a novel MTOC that is totally different from MTOCs previously found in either plant or animal cells.

【 授权许可】

Unknown