Functional characterization of cohesin subunit SCC1 in Trypanosoma brucei and dissection of mutant phenotypes in two life cycle stages

Gluenz, E. , Sharma, R., Carrington, M. and Gull, K. (2008) Functional characterization of cohesin subunit SCC1 in Trypanosoma brucei and dissection of mutant phenotypes in two life cycle stages. Molecular Microbiology, 69(3), pp. 666-680. (doi: 10.1111/j.1365-2958.2008.06320.x) (PMID:18554326) (PMCID:PMC2610385)

Abstract

In yeast and metazoa, structural maintenance of chromosome (SMC) complexes play key roles in chromosome segregation, architecture and DNA repair. The main function of the cohesin complex is to hold replicated sister chromatids together until segregation at anaphase, which is dependent on proteolytic cleavage of the cohesin subunit SCC1. Analysis of trypanosomatid genomes showed that the core cohesin and condensin complexes are conserved, but SMC5/6 is absent. To investigate the functional conservation of cohesin in eukaryotes distantly related to yeast and metazoa, we characterized the Trypanosoma brucei SCC1 orthologue. TbSCC1 is expressed prior to DNA synthesis at late G1, remains in the nucleus throughout S‐ and G2‐phases of the cell cycle and disappears at anaphase. Depletion of SCC1 by RNAi or expression of a non‐cleavable SCC1 resulted in karyokinesis failure. Using the dominant negative phenotype of non‐cleavable SCC1 we investigated checkpoint regulation of cytokinesis in response to mitosis failure at anaphase. In the absence of chromosome segregation, procyclic trypanosomes progressed through cytokinesis to produce one nucleated and one anucleate cell (zoid). In contrast, cytokinesis was incomplete in bloodstream forms, where cleavage was initiated but cells failed to progress to abscission. Kinetoplast duplication was uninterrupted resulting in cells with multiple kinetoplasts and flagella.

• Item Type: Articles
• Additional Information: This work was funded by The Wellcome Trust and EP Abraham Trust. R.S. held a PhD studentship funded by the Ministry of Science, Technology and Innovation, Malaysia. K.G. is a Wellcome Trust Principal Research Fellow.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gluenz, Dr Eva
• Authors: Gluenz, E., Sharma, R., Carrington, M., and Gull, K.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: Molecular Microbiology
• Publisher: Wiley
• ISSN: 0950-382X
• ISSN (Online): 1365-2958
• Published Online: 28 June 2008
• Copyright Holders: Copyright © 2008 The Authors
• First Published: First published in Molecular Microbiology 69(3):666-680
• Publisher Policy: Rreproduced in accordance with the publisher policy