Transposon tagging and molecular analysis of the maize regulatory locus opaque-2.
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.
Schmidt
R J
RJ
Biology Department, Brookhaven National Laboratory, Upton, NY 11973.
Burr
F A
FA
Burr
B
B
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
D004251:DNA Transposable Elements; D004262:DNA Restriction Enzymes