Recombination Analysis of the Human Minisatellite MsH42 Suggests the Existence of Two Distinct Pathways for Initiation and Resolution of Recombination at MsH42 in Rat Testes Nuclear Extracts
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- 作者：Francisco Boá ; n ; José ; Manuel Rodrí ; guez ; Susana Mouriñ ; o ; Miguel G. Blanco ; Ana Viñ ; as ; Laura Sá ; nchez ; and Jaime Gó ; mez-Má ; rquez
- 刊名：Biochemistry
- 出版年：2002
- 出版时间：February 19, 2002
- 年：2002
- 卷：41
- 期：7
- 页码：2166 - 2176
- 全文大小：613K
- 年卷期：v.41,no.7(February 19, 2002)
- ISSN：1520-4995
文摘
We have previously described a GC-rich human minisatellite, termed MsH42, which exists intwo allelic forms, long and short. Here, we have identified a third allele of medium length and localizedthe MsH42 locus in the chromosome 15q25.1 inside an intron belonging to a gene of unknown function.The recombinogenic potential of the three alleles was assayed in vitro incubating pBR322-based constructscontaining two copies of the minisatellite MsH42 with its flanking sequences, in the presence of rat testesnuclear extracts. This assay system was configured to monitor only reciprocal exchange type events andnot gene conversion. All MsH42 allelic sequences enhanced intramolecular homologous recombinationpromoting high rates (
76%) of equal crossover, the long allele showing the highest recombinogenicactivity. Removal of the MsH42 long allele flanking sequences, which are identical in the three alleles,provoked a decrease in the enhancement of recombination and in the frequency of equal crossovers,suggesting that these sequences are important for the recombinogenic activity and for the correct pairingbetween homologous sequences. The occurrence of some complex recombination events within theminisatellite MsH42 suggests the existence of processes related to polymerase slippage and unwindingwith reinvasion during the repair synthesis. Our findings point toward the existence of two distinctbiochemical pathways for initiation and resolution of recombination at the minisatellite MsH42. Finally,the in vitro recombination system employed in this study could provide an approach to dissect processesof repetitive DNA instability and recombination.
76%) of equal crossover, the long allele showing the highest recombinogenicactivity. Removal of the MsH42 long allele flanking sequences, which are identical in the three alleles,provoked a decrease in the enhancement of recombination and in the frequency of equal crossovers,suggesting that these sequences are important for the recombinogenic activity and for the correct pairingbetween homologous sequences. The occurrence of some complex recombination events within theminisatellite MsH42 suggests the existence of processes related to polymerase slippage and unwindingwith reinvasion during the repair synthesis. Our findings point toward the existence of two distinctbiochemical pathways for initiation and resolution of recombination at the minisatellite MsH42. Finally,the in vitro recombination system employed in this study could provide an approach to dissect processesof repetitive DNA instability and recombination.