title: Non-symmetrical cytosine methylation in tobacco pollen DNA.
abstract: We have detected sequence-specific non-symmetrical cytosine methylation within a 140 bp region of the promoter for the tobacco auxin-binding protein gene T85 in pollen DNA. Direct sequencing of the population of bisulphite reaction products showed that, in this region. 10 out of a possible 49 cytosine residues were methylated at a high frequency in pollen whereas the corresponding region from somatic cells (leaf DNA) did not show a detectable level of methylation. The context of these sites was 1 x m5CpTpC, 1 x m5CpGpT, 1 x m5CpCpT, 2 x m5CpTpT, 2 x m5CpGpG, and 3 x m5CpApT of which only m5CpGpG and m5CpGpT fitted the consensus sequence for symmetrical methylation in plants.
authors.affiliation: Friedrich Miescher-Institut, Basel, Switzerland.
authors.forename: E J
authors.initials: EJ
authors.lastname: Oakeley
authors.forename: J P
authors.initials: JP
authors.lastname: Jost
mesh_terms: D001483:Base Sequence; D003596:Cytosine / Q000032:analysis*; D018744:DNA, Plant / Q000737:chemistry*; D008745:Methylation; D008969:Molecular Sequence Data; D010937:Plant Growth Regulators; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins; D010947:Plants, Toxic; D011058:Pollen / Q000737:chemistry*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics; D017422:Sequence Analysis, DNA; D014026:Nicotiana / Q000737:chemistry
chemical_list: D018744:DNA, Plant; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C046131:auxin receptor, plant; D003596:Cytosine