Two Mutations in a Maize bronze-1 Allele Caused by Transposable Elements of the Ac-Ds Family Alter the Quantity and Quality of the Gene Product

• Published in: Genetics (Austin) 1988-11, Vol.120 (3), p.767-777
• Main Authors: Schiefelbein, J. W, Furtek, D. B, Dooner, H. K, Nelson-Jr., O. E
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Alleles; Anthocyanins - genetics; Base Sequence; Biological and medical sciences; Blotting, Southern; Classical and quantitative genetics. Population genetics. Molecular genetics; Cloning, Molecular; DNA - genetics; DNA Transposable Elements; Enzyme Stability; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Generalities. Genetics. Plant material; Genes. Genome; Genetics and breeding of economic plants; Glucosyltransferases - genetics; Investigations; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Mutation; Restriction Mapping; RNA - biosynthesis; Zea mays; Zea mays - genetics
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/120.3.767

The Dissociation (Ds) mutant, Bz-wm, of the maize bronze-1 (bz) locus conditions a leaky phenotype. Plants carrying this mutant allele synthesize a low amount of an altered Bz gene product, which leads to reduced anthocyanin pigmentation in the seed. The molecular analysis reported here shows that the Bz-wm mutant has a 406-bp Ds1 insertion located 63 bp 5' to the start of Bz transcription. Furthermore, the Bz-wm allele contains three additional base pairs within the second exon, relative to the wild-type Bz allele. These additional nucleotides are believed to be derived from the 8-bp target site duplication created by an Activator (Ac) element in a previous allele in the series. The biochemical and molecular analyses of Bz-wm and revertants of Bz-wm indicate that the three additional nucleotides are responsible for the altered enzyme stability, while the Ds1 element affects the steady-state level of Bz-specific protein and RNA. Since the two mutations present in the Bz-wm mutant were each caused by the action of the Ac-Ds transposable element system, these results provide new insights into the ways that transposable elements can modify maize gene expression.