title: Distribution of Activator (Ac) throughout the maize genome for use in regional mutagenesis.
abstract: A collection of Activator (Ac)-containing, near-isogenic W22 inbred lines has been generated for use in regional mutagenesis experiments. Each line is homozygous for a single, precisely positioned Ac element and the Ds reporter, r1-sc:m3. Through classical and molecular genetic techniques, 158 transposed Ac elements (tr-Acs) were distributed throughout the maize genome and 41 were precisely placed on the linkage map utilizing multiple recombinant inbred populations. Several PCR techniques were utilized to amplify DNA fragments flanking tr-Ac insertions up to 8 kb in length. Sequencing and database searches of flanking DNA revealed that the majority of insertions are in hypomethylated, low- or single-copy sequences, indicating an insertion site preference for genic sequences in the genome. However, a number of Ac transposition events were to highly repetitive sequences in the genome. We present evidence that suggests Ac expression is regulated by genomic context resulting in subtle variations in Ac-mediated excision patterns. These tr-Ac lines can be utilized to isolate genes with unknown function, to conduct fine-scale genetic mapping experiments, and to generate novel allelic diversity in applied breeding programs.
authors.affiliation: Boyce Thompson Institute, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Kolkman
authors.forename: Liza J
authors.initials: LJ
authors.lastname: Conrad
authors.forename: Phyllis R
authors.initials: PR
authors.lastname: Farmer
authors.forename: Kristine
authors.initials: K
authors.lastname: Hardeman
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Ahern
authors.forename: Paul E
authors.initials: PE
authors.lastname: Lewis
authors.forename: Ruairidh J H
authors.initials: RJ
authors.lastname: Sawers
authors.forename: Sara
authors.initials: S
authors.lastname: Lebejko
authors.forename: Paul
authors.initials: P
authors.lastname: Chomet
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Brutnell
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D003001:Cloning, Molecular; D004251:DNA Transposable Elements / Q000235:genetics*; D018744:DNA, Plant; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D017930:Genes, Reporter; D005821:Genetic Techniques; D014644:Genetic Variation; D018745:Genome, Plant; D006720:Homozygote; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid; D018626:Retroelements; D003313:Zea mays / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D018744:DNA, Plant; D018626:Retroelements