title: Analysis of maize brittle-1 alleles and a defective Suppressor-mutator-induced mutable allele.
abstract: A mutant allele of the maize brittle-1 (bt1) locus, brittle-1-mutable (bt1-m), was shown genetically and molecularly to result from the insertion of a defective Suppressor-mutator (dSpm) transposable element. An Spm-hybridizing restriction enzyme fragment, which cosegregates with the bt1-m allele and is absent from wild-type revertants of bt1-m, was identified and cloned. Non-Spm portions of it were used as probes to identify wild-type (Bt1) cDNAs in an endosperm library. The 4.3-kb bt1-m genomic clone contains a 3.3-kb dSpm, which is inserted in an exon and is composed of Spm termini flanking non-Spm sequences. RNA gel blot analyses, using a cloned Bt1 cDNA probe, indicated that Bt1 mRNA is present in the endosperm of developing kernels and is absent from embryo or leaf tissues. Several transcripts are produced by bt1-m. The deduced translation product from a 1.7-kb Bt1 cDNA clone has an apparent plastid transit peptide at its amino terminus and sequence similarity to several mitochondrial inner-envelope translocator proteins, suggesting a possible role in amyloplast membrane transport.
authors.affiliation: Laboratory of Genetics, University of Wisconsin, Madison 53706.
authors.forename: T D
authors.initials: TD
authors.lastname: Sullivan
authors.forename: L I
authors.initials: LI
authors.lastname: Strelow
authors.forename: C A
authors.initials: CA
authors.lastname: Illingworth
authors.forename: R L
authors.initials: RL
authors.lastname: Phillips
authors.forename: O E
authors.initials: OE
authors.lastname: Nelson
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA; D004251:DNA Transposable Elements; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic; D003313:Zea mays / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D008565:Membrane Proteins; D010940:Plant Proteins; D004247:DNA