title: Isolation and characterization of a 1.7-kb transposable element from a mutator line of maize.
abstract: We have cloned and sequenced a 1.7-kb Mu element from a Mutator line of maize and compared its structure to Mu1, a 1.4-kb element. With the exception of a 385-bp block of DNA present in the 1.7-kb element, these transposable elements are structurally similar, sharing terminally inverted and internal direct repeated sequences. Derivation of 1.4-kb elements from the 1.7-kb class via deletion of internal sequence is suggested by the finding that a portion of the extra DNA in Mu1.7 is part of a truncated direct repeat sequence in the 1.4-kb element. An abundant poly(A)+ RNA homologous to a portion of this extra DNA is present in several tissues of both Mutator and non-Mutator lines. Analysis of transcripts from an unstable mutant bronze 1 (bz) allele containing a Mu1.7 element inserted in an exon of the gene detects three species of poly(A)+ RNA that hybridize to a Bz1 (Bronze) gene probe: the largest contains the entire Mu1.7 element in the Bz1 gene transcript; another appears to be a spliced, chimeric transcript; the smallest is normal size Bz1 mRNA. The latter is most likely encoded by the normal-size alleles detected by Southern analysis of tissue expressing purple pigment, suggesting that normal gene function is restored by excision of the Mu1.7 element.
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004262:DNA Restriction Enzymes; D004251:DNA Transposable Elements; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D009710:Nucleotide Mapping; D010944:Plants / Q000235:genetics*; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D003313:Zea mays / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D012313:RNA; D004247:DNA; D004262:DNA Restriction Enzymes