JCB logo
BITPLANE Scientific Software
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 783K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Inoue, Y. H.
Right arrow Articles by Glover, D. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Inoue, Y. H.
Right arrow Articles by Glover, D. M.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

© The Rockefeller University Press, 0021-9525/2000//153 $5.00
The Journal of Cell Biology, Volume 149, Number 1, , 2000 153-166

Original Article

Orbit, a Novel Microtubule-Associated Protein Essential for Mitosis in Drosophila melanogaster



Yoshihiro H. Inouea,b, Maria do Carmo Avidesb,c, Michina Shirakia, Peter Deakb,c, Masamitsu Yamaguchia, Yoshio Nishimotoa, Akio Matsukagea, and David M. Gloverb,c

a Laboratory of Cell Biology, Aichi Cancer Center, Research Institute, Nagoya 464-8681, Japan
b Cell Cycle Genetics Research Group, Medical Sciences Institute, University of Dundee, Dundee DD1 4HN, Scotland
c Department of Genetics, University of Cambridge, Cambridge CB2 3EH, England
Drosophila Resource Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-Ku, Kyoto, 606-8585 Japan.81 75 724-771081 75 724-7788

yhinoue{at}drochan.bio.kit.ac.jp

We describe a Drosophila gene, orbit, that encodes a conserved 165-kD microtubule-associated protein (MAP) with GTP binding motifs. Hypomorphic mutations in orbit lead to a maternal effect resulting in branched and bent mitotic spindles in the syncytial embryo. In the larval central nervous system, such mutants have an elevated mitotic index with some mitotic cells showing an increase in ploidy. Amorphic alleles show late lethality and greater frequencies of hyperploid mitotic cells. The presence of cells in the hypomorphic mutant in which the chromosomes can be arranged, either in a circular metaphase or an anaphase-like configuration on monopolar spindles, suggests that polyploidy arises through spindle and chromosome segregation defects rather than defects in cytokinesis. A role for the Orbit protein in regulating microtubule behavior in mitosis is suggested by its association with microtubules throughout the spindle at all mitotic stages, by its copurification with microtubules from embryonic extracts, and by the finding that the Orbit protein directly binds to MAP-free microtubules in a GTP-dependent manner.

Key Words: mitosis • microtubule-associated protein • Drosophila melanogaster • mitotic spindle • cen- • trosome

© 2000 The Rockefeller University Press

Michina Shiraki's present address is Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayama-cho, lkoma, Nara 630-0101, Japan.

Abbreviations used in this paper: asp, abnormal spindle; aur, aurora; GST, glutathione S-transferase; MAP, microtubule-associated protein; mgr, merry-go-round.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?




  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents