Formation and repair of O6-methylguanine in recombination hot spots of plant chromosomes

✍ Scribed by Pawel Baranczewski; Peter Nehls; Rigomar Rieger; Uta Pich; Manfred F. Rajewsky; Ingo Schubert

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 96 KB
• Volume: 29
• Category: Article
• ISSN: 0893-6692
• DOI: 10.1002/(sici)1098-2280(1997)29:4<394::aid-em8>3.0.co;2-a

✦ Synopsis

Mutagen-induced chromatid aberrations are not DNA as well as in FokI sequences of the field bean randomly distributed along the metaphase chromo-after exposure to MNU. In either case, similar numsomes. In the field bean (Vicia faba), defined late-bers of adducts per nucleotide were found immedireplicating and transcriptionally inactive hetero-ately after treatment as well as after 18 hours of chromatic regions are preferentially involved. After recovery, when most adducts were removed and exposure to the alkylating agent N-methyl-N-nitrosignificant amounts of chromatid aberrations were sourea (MNU) (10 03 M, 1 hour), 70% of all aberra-detectable. Peculiarities of long FokI element arrays tions are clustered within 6 segments containing tan-(e.g., formation of specific tertiary structures), redemly repeated FokI elements of 59 bp, which com-sulting in error-prone recombination repair, rather prise Ç10% of the genome. Using immuno-slot-blot than preferential formation or delayed repair of O 6analyses, we have studied the frequency of O 6 -MeG are apparently responsible for aberration methylguanine (O 6 -MeG), a mutagenic lesion im-clustering in these hot spot regions.