Hrs1p/Mcp6p on the meiotic SPB organizes astral microtubule arrays for oscillatory nuclear movement

Curr Biol. 2005 Aug 23;15(16):1479-86. doi: 10.1016/j.cub.2005.07.058.

Abstract

Microtubules and the motor protein dynein play pivotal roles in the movement and positioning of the nucleus and cytoplasmic organelles in a cell. In fission yeast, oscillatory movement of the nucleus termed horsetail nuclear movement (HNM) has been observed during meiotic prophase. HNM is led by an astral microtubule array emanating from the spindle pole body (SPB), a centrosome-equivalent organelle in yeasts, aided by the dynein-dynactin complex, and is proposed to facilitate the alignment of homologous chromosomes necessary for efficient meiotic recombination. Here we show that a meiosis-specific SPB component Hrs1p (also known as Mcp6p) is a key molecule to remodel microtubules into the horsetail-astral array (HAA). Deletion of Hrs1p impaired HAA formation, leading to compromised HNM. Ectopic expression of Hrs1p during the mitotic cell cycle resulted in the formation of a HAA-like astral microtubule array, which drove an oscillatory nuclear movement in interphase cells. Hrs1p interacted with components of the gamma-tubulin ring complex (gamma-TuRC) as well as with a meiotic SPB component. We propose that Hrs1p facilitates formation of the HAA, responsible for the vigorous HNM, by stabilizing connection between the SPB and minus ends of microtubules.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Nucleus / physiology*
  • Computational Biology
  • Microscopy, Fluorescence
  • Microtubules / metabolism*
  • Movement / physiology
  • Schizosaccharomyces
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Spindle Apparatus / metabolism*
  • Tubulin / metabolism

Substances

  • Hrs1 protein, S pombe
  • Schizosaccharomyces pombe Proteins
  • Tubulin