Gnarley1 is a dominant mutation in the knox4 homeobox gene affecting cell shape and identity.
Maize leaves have a stereotypical pattern of cell types organized into discrete domains. These domains are altered by mutations in knotted1 (kn1) and knox (for kn1-like homeobox) genes. Gnarley (Gn1) is a dominant maize mutant that exhibits many of the phenotypic characteristics of the kn1 family of mutants. Gn1 is unique because it changes parameters of cell growth in the basal-most region of the leaf, the sheath, resulting in dramatically altered sheath morphology. The strongly expressive allele Gn1-R also gives rise to a floral phenotype in which ectopic carpels form. Introgression studies showed that the severity of the Gn1-conferred phenotype is strongly influenced by genetic background. Gn1 maps to knox4, and knox4 is ectopically expressed in plants with the Gn1-conferred phenotype. Immunolocalization experiments showed that the KNOX protein accumulates at the base of Gn1 leaves in a pattern that is spatially and temporally correlated with appearance of the mutant phenotype. We further demonstrate that Gn1 is knox4 by correlating loss of the mutant phenotype with insertion of a Mutator transposon into knox4.
Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA.
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D000483:Alleles; D000595:Amino Acid Sequence; D005799:Genes, Dominant; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D018515:Plant Leaves; D010940:Plant Proteins; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000166:cytology / Q000235:genetics*
D018398:Homeodomain Proteins; C121064:Knox4 protein, Zea mays; D010940:Plant Proteins