A deletion adjacent to the maize transposable element Mu-1 accompanies loss of Adh1 expression.

Abstract

Insertion of the maize transposable element Mu‐1 into the first intron of the alcohol dehydrogenase locus (Adh1) of maize produced mutant Adh1‐S3034 with 40% of the wild‐type level of protein and mRNA. Continued instability at this locus resulted in secondary mutations with lower levels of protein expression. One of these, Adh1‐S3034a, has no detectable ADH1 expression. This paper describes the precise nature of the changes in the Adh1 gene that gave rise to the S3034a allele. The Mu‐1 element is still present in the mutant, but Adh1 sequences immediately adjacent to the element are deleted. The deletion starts precisely at the Mu‐1 insertion site and extends 74 bp leftward removing part of the first intron, the intron:exon junction and 2 bp of the eleventh amino acid codon in the first exon of the gene. Tests for reversion within the somatic tissue of plants show that mutant S3034a, unlike its progenitor, is stably null for ADH1 activity.

Macrotransposition and Other Complex Chromosomal Restructuring in Maize by Closely Linked Transposons in Direct Orientation

“…These rearrangements, with one end point at a transposon terminus, were first detected next to insertion sequence elements in bacteria (Reif and Saedler, 1975) and have been reported for several plant transposon systems (Dooner, 1985;Taylor and Walbot, 1985;Martin et al, 1988). They are readily explained by abortive transposition reactions involving only one element end.…”

Functional Analysis of Maize RAD51 in Meiosis and Double-Strand Break Repair

“…Mu-insertion alleles (Brown et al 1989;Levy et al 1989;Schnable et al 1989), $1% of gametes carry deletions adjacent to a given Mu insertion (Taylor and Walbot 1985;Levy and Walbot 1991;Das and Martienssen 1995). A PCR-based screen modified from that described by Das and Martienssen (1995) was used to identify rare derivatives of rad51 TUSC alleles that contained deletions adjacent to the Mu insertions.…”

Site-Selected Transposon Mutagenesis at the hcf106 Locus in Maize

“…Second, Mu elements share long terminal inverted repeats that are very similar between different classes of element, providing sufficient sequence for multiple nested primers (Chandler and Hardeman, 1992). Third, germina1 excision is rare, whereas transpositions and flanking deletions are very common: Mul elements at the Alcohol dehydrogenasel and Bronze2 loci in maize are known to generate flanking deletions resulting in null alleles at frequencies approaching 1% (Taylor and Walbot, 1985;Levy and Walbot, 1991). Such deletions are typically less than 100 bp and are thought to result from either abortive transposition or illegitimate recombination between the element and the gene.…”