| Autor: |
Le, Long, Ayer, Stephen, Place, Allen R., Benyajati, Cheeptip |
| Zdroj: |
Biochemical Genetics; August 1990, Vol. 28 Issue: 7-8 p367-387, 21p |
| Abstrakt: |
Two formaldehyde-induced mutations at the DrosophilaAdh locus (Adhfn45 andAdhfn46) were analyzed by determining RNA structures at different developmental stages, polymerase chain reaction (PCR) amplification of the affected genomic regions, and direct sequencing of the resulting double-stranded DNA fragments.Adhfn46 adults and larvae accumulate abundant ADH-like distal (adult) and proximal (larval) transcripts that are shorter than transcripts in wild-type flies by a lesion located in the second ADH protein-coding exon. Direct sequencing of the amplified DNA region showed thatAdhfn46 contains a 69-bp in-frame deletion that removes 23 amino acids near one border of the second exon. Consistent with these findings, we observed a shorter ADHfn46 protein present at only 3% of wild-type levels. In contrast,Adhfn45 adults and larvae accumulate much smaller amounts of ADH-like distal and proximal transcripts. Both RNAs have an identical aberration in RNA splicing of the 65-base intron sequence. Direct sequencing of the amplified mutated DNA region showed thatAdhfn45 contains a 21-bp deletion that removed and rearranged DNA at the 5' splice junction of the 65-bp intron. No ADH cross-reacting material is detected inAdhfn45 flies. Direct-repeat sequences (3–11 bp) are present flanking and within the mutated DNA regions. The patterns of DNA deletion and deletion accompanied by sequence addition at the mutant sites suggest a slipped mispairing mechanism during DNA replication or repair that involves local DNA homology. |
| Databáze: |
Supplemental Index |
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