Interpolar spindle microtubules in PTK cells.

• DOI: 10.1083/jcb.123.6.1475
• Publication Date: 2004-05-15T00:22:22Z
• Authors: D N Mastronarde; K L McDonald; R Ding; J R McIntosh
• Keywords: Spindle pole body; Spindle checkpoint

Spindle microtubules (MTs) in PtK1 cells, fixed at stages from metaphase to telophase, have been reconstructed using serial sections, electron microscopy, and computer image processing. We studied the class of MTs that form an interdigitating system connecting two spindle poles (interpolar or ipMTs) their relationship attach kinetochores (kMTs). Viewed cross section, ipMTs cluster with antiparallel near neighbors throughout mitosis; this bundling becomes much more pronounced as anaphase proceeds. While minus ends most kMTs are poles, those spread over half length, least 50% lying > 1.5 microns poles. Longitudinal views ipMT bundles demonstrate a major rearrangement plus between mid- late B. However, these do not move appreciably farther midplane, suggesting sliding contributes little The markedly clustered A. These lie close frequently than would be expected by chance, specific interaction. As sister separate shorten, remain associated but many released kMT bundles, allowing pole away elongates.