Biomaterial Database

Paramutation of the r1 locus of maize is associated with increased cytosine methylation. 1998

E L Walker

Biology Department, University of Massachusetts, Amherst 01003, USA. ewalker@bio.umass.edu

In paramutation two alleles of a gene interact so that one of the alleles is epigenetically silenced. The silenced state is then genetically transmissible for many generations. The large (220 kbp) multigenic complex R-r is paramutable: its level of expression is changed during paramutation. R-r was found to exhibit increases in its level of cytosine methylation (C-methylation) following paramutation. These C-methylation changes are localized to the 5' portions of the two genes in the complex that are most sensitive to paramutation. These methylation changes flank a small region called sigma that is thought to have been derived from a transposon named doppia. A mutant derivative of R-r that has a deletion of the sigma region fails to become methylated under conditions in which R-r is heavily methylated. This suggests that the presence of sigma sequences at the locus is required for the methylation changes that are observed following paramutation.

UI	MeSH Term	Description	Entries
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009687	Nuclear Proteins	Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.	Nucleolar Protein,Nucleolar Proteins,Nuclear Protein,Protein, Nuclear,Protein, Nucleolar,Proteins, Nuclear,Proteins, Nucleolar
D010940	Plant Proteins	Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which PLANT PROTEINS, DIETARY is available.	Plant Protein,Protein, Plant,Proteins, Plant
D002874	Chromosome Mapping	Any method used for determining the location of and relative distances between genes on a chromosome.	Gene Mapping,Linkage Mapping,Genome Mapping,Chromosome Mappings,Gene Mappings,Genome Mappings,Linkage Mappings,Mapping, Chromosome,Mapping, Gene,Mapping, Genome,Mapping, Linkage,Mappings, Chromosome,Mappings, Gene,Mappings, Genome,Mappings, Linkage
D003313	Zea mays	A plant species of the family POACEAE. It is a tall grass grown for its EDIBLE GRAIN, corn, used as food and animal FODDER.	Corn,Indian Corn,Maize,Teosinte,Zea,Corn, Indian
D003596	Cytosine	A pyrimidine base that is a fundamental unit of nucleic acids.
D017343	Genes, Plant	The functional hereditary units of PLANTS.	Plant Genes,Gene, Plant,Plant Gene
D017384	Sequence Deletion	Deletion of sequences of nucleic acids from the genetic material of an individual.	Deletion Mutation,Deletion Mutations,Deletion, Sequence,Deletions, Sequence,Mutation, Deletion,Mutations, Deletion,Sequence Deletions
D018257	Helix-Loop-Helix Motifs	Recurring supersecondary structures characterized by 20 amino acids folding into two alpha helices connected by a non-helical "loop" segment. They are found in many sequence-specific DNA-BINDING PROTEINS and in CALCIUM-BINDING PROTEINS.	HLH Motifs,Helix-Loop-Helix Domain,Helix-Loop-Helix Domains,Helix-Loop-Helix Motif,Motifs, Helix-Loop-Helix,HLH Motif,Helix Loop Helix Domain,Helix Loop Helix Domains,Helix Loop Helix Motif,Helix Loop Helix Motifs,Motif, HLH,Motif, Helix-Loop-Helix,Motifs, HLH,Motifs, Helix Loop Helix
D019175	DNA Methylation	Addition of methyl groups to DNA. DNA methyltransferases (DNA methylases) perform this reaction using S-ADENOSYLMETHIONINE as the methyl group donor.	DNA Methylations,Methylation, DNA,Methylations, DNA