title: Self-incompatibility: Smi silences through a novel sRNA pathway.
abstract: Self-incompatibility in Brassicaceae is determined by the interaction between S-Locus Protein 11 (SP11) on the pollen and S-receptor kinase (SRK) in the stigma. Pollen from heterozygotes generally displays products of both SP11 alleles, but in some heterozygotes SP11 expression is monoallelic, with one allele (SP11(R)) being silenced by promoter methylation. An exciting development in understanding the mechanism behind monoallelic silencing came recently when Y. Tarutani et al. [Nature 2010;466:983-986] identified a 24-nucleotide sRNA (termed Smi) derived from a non-coding gene within the dominant S-haplotype, and suggested that Smi directs promoter methylation. We propose that rather than having a direct effect on DNA methylation, Smi is the first step in a novel cis-acting siRNA pathway that directs widespread monoallelic SP11(R) promoter methylation.
authors.affiliation: CSIRO Plant Industry, Canberra ACT 2601, Australia. jean.finnegan@csiro.au
authors.forename: E Jean
authors.initials: EJ
authors.lastname: Finnegan
authors.forename: Dacheng
authors.initials: D
authors.lastname: Liang
authors.forename: Ming-Bo
authors.initials: MB
authors.lastname: Wang
mesh_terms: D000483:Alleles; D019607:Brassicaceae / Q000235:genetics* / Q000502:physiology; D019175:DNA Methylation / Q000235:genetics; D035264:Flowers / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D020868:Gene Silencing; D005799:Genes, Dominant; D006239:Haplotypes / Q000235:genetics; D006579:Heterozygote; D010641:Phenotype; D051479:Plant Infertility / Q000235:genetics* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011058:Pollen / Q000235:genetics / Q000378:metabolism; D054817:Pollination / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D058727:RNA, Small Untranslated / Q000235:genetics*; D012098:Reproduction / Q000235:genetics / Q000502:physiology
chemical_list: D010940:Plant Proteins; D018749:RNA, Plant; D058727:RNA, Small Untranslated; C431526:SP11 protein, Brassica; D011494:Protein Kinases; C079832:S-receptor kinase