A new allele of the duplicated 27kD zein locus of maize generated by homologous recombination.
The 27kD zein storage protein locus in many inbred lines of maize consists of a tandem duplication of 12kb, with an expressed gene in each repeat, termed A and B. A single-copy allele with only the A gene can be generated from this duplication in particular stocks of the maize inbred line A188 by a mitotic process that includes a crossover at the 3' regions of the two genes (1). Here, we characterize a second single-copy allele with only the B gene, found in different stocks of A188. This allele arises from a homologous recombination at the highly conserved 5' regions of the two repeats, and cloning and sequencing of this allele define the crossover region. The A and B genes in the duplicated allele were previously shown to be expressed at different levels; this difference remains unchanged in either recombinant allele. Therefore, the crossover points of these two recombinant alleles define the borders of cis-acting sequences responsible for the differential expression of the two genes.
Das
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Waksman Institute, Rutgers, State University of New Jersey, Piscataway 08855-0759.
Poliak
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Ward
K
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Messing
J
J
D000483:Alleles; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004247:DNA; D015870:Gene Expression; D008969:Molecular Sequence Data; D005810:Multigene Family; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D003313:Zea mays / Q000235:genetics*; D015028:Zein / Q000235:genetics*
D004247:DNA; D015028:Zein