The same mammalian replicon yields distinct recombination products in different cell lines

Vu, Huy Khang; Delbecchi, Louis; Bourgaux-Ramoisy, Danielle; Bourgaux, Pierre

doi:10.1016/s0021-9258(18)31588-6

Cited by 6 publications

(1 citation statement)

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“…It has generally been assumed that such recombination events would be dependent upon DNA replication (21,22,(24)(25)(26), and that the need for LT in recombination would thus reflect its role in the initiation and/or propagation of replication (27). However, results from one of our laboratories have suggested for LT a role in recombination distinct from that played in replication (28), such that LT would directly determine the nature of the recombination product (29). Prior to the development of a suitable in vitro recombination system, we have re-examined the effect of LT on DNA structure, taking into consideration that recombinases consistently display topoisomerase activity (30).…”

Section: Introductionmentioning

confidence: 99%

Topoisomerase activity associated with SV40 large tumor antigen

Marton¹,

Jean²,

Delbecchi³

et al. 1993

Nucl Acids Res

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Purified preparations of simian virus 40 (SV40) large tumor antigen (LT) from three different sources, including LT expressed from a recombinant baculovirus, were found to relax negatively supercoiled cyclic DNA molecules, whether or not they contained SV40 sequences. Relaxation was stimulated by MgCl2 but not by ATP, and inhibited by camptothecin, suggesting the involvement of an enzymatic activity similar to that of topoisomerase I (topo I). However, the pH requirements for relaxation by respectively LT and topo I are different. Also, antibodies reacting with LT inhibited relaxation by preparations of LT but not topo I, whereas antibodies inhibiting relaxation by topo I had no effect on relaxation by LT. Reconstruction experiments suggested that both procedures used to purify LT, immunoaffinity chromatography and DEAE-Sepharose chromatography, separate topo I from LT. Finally, relaxing activity was found in over 40 preparations of LT, and in the few instances where activity could not be found, it probably had been lost during storage, rather than absent from the start. Whereas these results seem to exclude that the activity being detected is that of a contaminant of LT, they would be consistent with this activity being that of a stable topo-LT complex, or else intrinsic to LT itself.

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Section: Introductionmentioning

confidence: 99%

Topoisomerase activity associated with SV40 large tumor antigen

Marton¹,

Jean²,

Delbecchi³

et al. 1993

Nucl Acids Res

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Double-strand DNA break repair with replication slippage on two strands: a novel mechanism of deletion formation

et al. 2006

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We have characterized an unusual family with two different androgen receptor (AR) gene deletions, in which we propose a novel mechanism of deletion formation has occurred. Affected individuals have the X-linked disorder androgen insensitivity syndrome, and we previously showed that different family members have deletions of different exons of the AR gene. We have now fully sequenced the deletions from affected individuals, and confirmed the presence of different deletions in different affected family members. Most affected and heterozygote individuals have a 4,430-bp deletion of exon 5 that occurred between repeated GTGGCAT motifs in introns 4 and 5. One affected hemizygous individual has a 4,033-bp deletion of exons 6 and 7 that occurred between repeated CCTC motifs in introns 5 and 7. The intron 5 breakpoint junctions of the two deletions are only 11 bp apart. Surprisingly, the maternal grandmother of the original index case was found to be mosaic for both deletional events, as well as having the normal AR gene. Karyotyping ruled out 47,XXX trisomy, indicating triple mosaicism for the two different deleted AR alleles and a normal AR allele. This triple mosaicism must have occurred early in embryonic development, as both deletions were passed on to different children. Based on these findings, we propose a novel mechanism of deletion formation. We suggest that during AR gene replication, a double strand DNA break occurred in intron 5, and that a variant of replication slippage occurred on both newly synthesized strands between the repeat motifs of microhomology, leading to the formation of the two different AR gene deletions.

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Involvement of Minor Structural Proteins in Recombination of Polyoma Virus DNA

et al. 2000

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We have previously observed that a polyoma-mouse chimeric DNA molecule (RmI) in which the murine DNA insert is flanked by directly repeated viral sequences is effectively converted into unit-length polyoma DNA upon transfection of permissive mouse cells. This intramolecular recombination event appears to be dependent on VmP1, a protein encoded by RmI which includes the 328 N-terminal amino acids of polyoma VP1, and nine amino acids of murine origin carrying the C-terminus of the protein. We report here that introducing mutations into the VP2/VP3 coding sequence reduces the ability of RmI to generate polyoma DNA, even though the same mutations seem to exert little or no effect on the ability of polyoma DNA to either replicate or accumulate inside transfected cells. A mutation affecting VP2 alone being as effective as one that affects both VP2 and VP3, VP2 appears to be playing a critical role in recombination.

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The same mammalian replicon yields distinct recombination products in different cell lines

Cited by 6 publications

References 1 publication

Topoisomerase activity associated with SV40 large tumor antigen

Topoisomerase activity associated with SV40 large tumor antigen

Double-strand DNA break repair with replication slippage on two strands: a novel mechanism of deletion formation

Involvement of Minor Structural Proteins in Recombination of Polyoma Virus DNA

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