Analysis of biological noise in the flagellar length control system

David Bauer; Hiroaki Ishikawa; Kimberly A Wemmer; Nathan L Hendel; Jane Kondev; Wallace F Marshall

doi:10.1016/j.isci.2021.102354

Analysis of biological noise in the flagellar length control system

iScience. 2021 Mar 23;24(4):102354. doi: 10.1016/j.isci.2021.102354. eCollection 2021 Apr 23.

Authors

David Bauer¹, Hiroaki Ishikawa¹, Kimberly A Wemmer¹, Nathan L Hendel¹, Jane Kondev², Wallace F Marshall^{1

3}

Affiliations

¹ Department of Biochemistry & Biophysics, University of California, San Francisco, 600 16th St., San Francisco, CA, USA.
² Department of Physics, Brandeis University, Abelson-Bass-Yalem Building, 97-301, Waltham, MA, USA.
³ Center for Cellular Construction, University of California, San Francisco, 600 16th St., San Francisco, CA, USA.

Abstract

Any proposed mechanism for organelle size control should be able to account not only for average size but also for the variation in size. We analyzed cell-to-cell variation and within-cell variation of length for the two flagella in Chlamydomonas, finding that cell-to-cell variation is dominated by cell size, whereas within-cell variation results from dynamic fluctuations. Fluctuation analysis suggests tubulin assembly is not directly coupled with intraflagellar transport (IFT) and that the observed length fluctuations reflect tubulin assembly and disassembly events involving large numbers of tubulin dimers. Length variation is increased in long-flagella mutants, an effect consistent with theoretical models for flagellar length regulation. Cells with unequal flagellar lengths show impaired swimming but improved gliding, raising the possibility that cells have evolved mechanisms to tune biological noise in flagellar length. Analysis of noise at the level of organelle size provides a way to probe the mechanisms determining cell geometry.

Keywords: Biological Sciences; Biophysics; Cell Biology; Mathematical Biosciences; Molecular Biology.

Abstract

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