Ten members of the Arabidopsis gene family encoding methyl-CpG-binding domain proteins are transcriptionally active and at least one, AtMBD11, is crucial for normal development.
Animal proteins that contain a methyl-CpG-binding domain (MBD) are suggested to provide a link between DNA methylation, chromatin remodelling and gene silencing. However, some MBD proteins reside in chromatin remodelling complexes, but do not have specific affinity for methylated DNA. It has recently been shown that the Arabidopsis genome contains 12 putative genes encoding proteins with domains similar to MBD, of which at least three bind symmetrically methylated DNA. Using a bioinformatics approach, we have identified additional domains in a number of these proteins and, on this basis and extended sequence similarity, divided the proteins into subgroups. Using RT-PCR we show that 10 of the AtMBD genes are active and differentially expressed in diverse tissues. To investigate the biological significance of AtMBD proteins, we have transformed Arabidopsis with a construct aimed at RNA interference with expression of the AtMBD11 gene, normally active in most tissues. The resulting 35S::AtMBD11-RNAi plants displayed a variety of phenotypic effects, including aerial rosettes, serrated leaves, abnormal position of flowers, fertility problems and late flowering. Arabidopsis lines with reduced expression of genes involved in chromatin remodelling and transgene silencing show similar phenotypes. Our results suggest an important role for AtMBD proteins in plant development.
Berg
Anita
A
Division of Cell and Molecular Biology, Department of Biology, University of Oslo, PO Box 1031 Blindern, N-0315 Oslo, Norway.
Meza
Trine J
TJ
Mahić
Mirela
M
Thorstensen
Tage
T
Kristiansen
Kjetil
K
Aalen
Reidunn B
RB
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D015152:Blotting, Northern; D002467:Cell Nucleus / Q000378:metabolism; D018899:CpG Islands / Q000235:genetics*; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D010641:Phenotype; D030821:Plants, Genetically Modified; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D008164:Luminescent Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins