The RecQ helicase AtRECQ4A is required to remove inter-chromosomal telomeric connections that arise during meiotic recombination in Arabidopsis
Article first published online: 30 DEC 2010
© 2010 The Authors. The Plant Journal © 2010 Blackwell Publishing Ltd
The Plant Journal
Volume 65, Issue 3, pages 492–502, February 2011
How to Cite
Higgins, J. D., Ferdous, M., Osman, K. and Franklin, F. C. H. (2011), The RecQ helicase AtRECQ4A is required to remove inter-chromosomal telomeric connections that arise during meiotic recombination in Arabidopsis. The Plant Journal, 65: 492–502. doi: 10.1111/j.1365-313X.2010.04438.x
- Issue published online: 26 JAN 2011
- Article first published online: 30 DEC 2010
- Accepted manuscript online: 20 NOV 2010 10:22AM EST
- Received 15 October 2010; revised 12 November 2010; accepted 18 November 2010; published online 30 December 2010.
RecQ helicases are a conserved group of proteins with a role in the maintenance of genome integrity. In Saccharomyces cerevisiae (budding yeast), meiotic recombination is increased in the absence of the RecQ helicase Sgs1. Here we investigated the potential meiotic role of the Sgs1 homologue AtRECQ4A and the closely related AtRECQ4B. Both proteins have been shown to function during recombination in somatic cells, but so far their meiotic role has not been investigated. Both AtRECQ4A and AtRECQ4B were expressed in reproductive tissues. Although immunolocalization studies showed that AtRECQ4A associates with recombination intermediates, we found no evidence that its loss or that of AtRECQ4B had a significant effect on meiotic cross-overs, suggesting functional redundancy with other RECQ family members. Nevertheless, pollen viability decreased in Atrecq4A, resulting in a reduction in fertility, although this was not the case in Atrecq4B. Cytological analysis revealed chromatin bridges between the telomeres of non-homologous chromosomes in Atrecq4A at metaphase I, in some instances accompanied by chromosome fragmentation at anaphase I. The bridges required telomeric repeats and were dependent on meiotic recombination. Immunolocalization confirmed the association of AtRECQ4A with the telomeres during prophase I, which we propose enables dissolution of recombination-dependent telomeric associations. Thus, this study has identified a hitherto unknown role for a member of the RECQ helicase family during meiosis that contributes to the maintenance of chromosome integrity. As telomere structure is generally conserved, it seems likely that these associations may arise during meiosis in other species, where they must also be removed.