The role of the MCM2-7 helicase complex during Arabidopsis seed development

Herridge, R. P., Day, R. C., Macknight, R. C. (September 2014) The role of the MCM2-7 helicase complex during Arabidopsis seed development. Plant Molecular Biology, 86 (1-2). pp. 69-84. ISSN 01674412

URL: http://www.ncbi.nlm.nih.gov/pubmed/24947836
DOI: 10.1007/s11103-014-0213-x

Abstract

The MINICHROMOSOME MAINTENANCE 2-7 (MCM2-7) complex, a ring-shaped heterohexamer, unwinds the DNA double helix ahead of the other replication machinery. Although there is evidence that individual components might have other roles, the essential nature of the MCM2-7 complex in DNA replication has made it difficult to uncover these. Here, we present a detailed analysis of Arabidopsis thalianamcm2-7 mutants and reveal phenotypic differences. The MCM2-7 genes are coordinately expressed during development, although MCM7 is expressed at a higher level in the egg cell. Consistent with a role in the egg cell, heterozygous mcm7 mutants resulted in frequent ovule abortion, a phenotype that does not occur in other mcm mutants. All mutants showed a maternal effect, whereby seeds inheriting a maternal mutant allele occasionally aborted later in seed development with defects in embryo patterning, endosperm nuclear size, and cellularization, a phenotype that is variable between subunit mutants. We provide evidence that this maternal effect is due to the necessity of a maternal store of MCM protein in the central cell that is sufficient for maintaining seed viability and size in the absence of de novo MCM transcription. Reducing MCM levels using endosperm-specific RNAi constructs resulted in the up-regulation of DNA repair transcripts, consistent with the current hypothesis that excess MCM2-7 complexes are loaded during G1 phase, and are required during S phase to overcome replicative stress or DNA damage. Overall, this study demonstrates the importance of the MCM2-7 subunits during seed development and suggests that there are functional differences between the subunits. © 2014 Springer Science+Business Media Dordrecht.

Item Type: Paper
Uncontrolled Keywords: Arabidopsis DNA damage DNA helicase DNA repair DNA replication Seed development
Subjects: organism description > plant > Arabidopsis
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > helicase
CSHL Authors:
Communities: CSHL labs > Martienssen lab
Depositing User: Matt Covey
Date: September 2014
Date Deposited: 11 Jul 2014 15:12
Last Modified: 08 Sep 2014 15:59
Related URLs:
URI: http://repository.cshl.edu/id/eprint/30495

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