Genetic analysis of functional redundancy of BRM ATPase and ATSWI3C subunits of Arabidopsis SWI/SNF chromatin remodelling complexes.
In yeast and mammals, ATP-dependent chromatin remodelling complexes of the SWI/SNF family play critical roles in the regulation of transcription, cell proliferation, differentiation and development. Homologues of conserved subunits of SWI/SNF-type complexes, including Snf2-type ATPases and SWI3-type proteins, participate in analogous processes in Arabidopsis. Recent studies indicate a remarkable similarity between phenotypic effects of mutations in the SWI3 homologue ATSWI3C and bromodomain-ATPase BRM genes. To verify the extent of functional similarity between BRM and ATSWI3C, we have constructed atswi3c brm double mutants and compared their phenotypic traits to those of simultaneously grown single atswi3c and brm mutants. In addition to inheritance of characteristic developmental abnormalities shared by atswi3c and brm mutants, some additive brm-specific traits were also observed in the atswi3c brm double mutants. Unlike atswi3c, the brm mutation results in the enhancement of abnormal carpel development and pollen abortion leading to complete male sterility. Despite the overall similarity of brm and atswi3c phenotypes, a critical requirement for BRM in the differentiation of reproductive organs suggests that its regulatory functions do not entirely overlap those of ATSWI3C. The detection of two different transcript isoforms indicates that BRM is regulated by alternative splicing that creates an in-frame premature translation stop codon in its SNF2-like ATPase coding domain. The analysis of Arabidopsis mutants in nonsense-mediated decay suggests an involvement of this pathway in the control of alternative BRM transcript level.
Archacki
Rafal
R
Laboratory of Plant Molecular Biology, University of Warsaw, Pawinskiego 5A, 02-106, Warsaw, Poland.
Sarnowski
Tomasz J
TJ
Halibart-Puzio
Joanna
J
Brzeska
Katarzyna
K
Buszewicz
Daniel
D
Prymakowska-Bosak
Marta
M
Koncz
Csaba
C
Jerzmanowski
Andrzej
A
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D017398:Alternative Splicing; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern; D015153:Blotting, Western; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D008855:Microscopy, Electron, Scanning; D016254:Mutagenesis, Insertional; D009154:Mutation; D010641:Phenotype; D011058:Pollen / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013489:Suppression, Genetic
C463463:ATSWI3B protein, Arabidopsis; C544356:ATSWI3C protein, Arabidopsis; D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D021122:Protein Subunits; D016601:RNA-Binding Proteins; C036483:T-DNA; D000251:Adenosine Triphosphatases; C514541:BRM protein, Arabidopsis