title: Transposon tagging and molecular analysis of the maize regulatory locus opaque-2.
abstract: Genetic analyses suggested that the opaque-2 (o2) locus in maize acts as a positive, transacting, transcriptional activator of the zein seed storage-protein genes. Because isolation of the gene is requisite to understanding the molecular details of this regulation, transposon mutagenesis with the transposable element suppressor-mutator (Spm) was carried out, and three mutable o2 alleles were obtained. One of these alleles contained an 8.3-kilobase autonomous Spm, another a 6.8-kilobase nonautonomous Spm, and the third an unidentified transposon that is unrelated to Spm. A DNA sequence flanking the autonomous Spm insertion was verified to be o2-specific and provided a probe to clone a wild-type allele. Northern blots indicated that the gene is expressed in wild-type endosperm but not in leaf tissues or in endosperms homozygous for a mutant allele of the O2 gene. A transcript was detected in endosperms homozygous for mutations at opaque-7 and floury-2, an indication that O2 expression is independent of these two other putative regulators of zein synthesis.
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, NY 11973.
authors.forename: R J
authors.initials: RJ
authors.lastname: Schmidt
authors.forename: F A
authors.initials: FA
authors.lastname: Burr
authors.forename: B
authors.initials: B
authors.lastname: Burr
mesh_terms: D000483:Alleles; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004251:DNA Transposable Elements; D005809:Genes, Regulator; D006720:Homozygote; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010944:Plants / Q000235:genetics*; D003313:Zea mays / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D004262:DNA Restriction Enzymes