Cleavage of concatemeric DNA at the internal junction of 'translocation' mutants of pseudorabies virus and inversion of their L component appear to be linked
| Autor: | Tamar Ben-Porat, Z Q Lu, Sabina Kupershmidt, G F Rall |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Inverted repeat
Genetic Linkage education Mutant Molecular Sequence Data Chromosomal translocation Chick Embryo Genome Viral Biology Cleavage (embryo) Genome Homology (biology) Translocation Genetic chemistry.chemical_compound Virology Gene duplication Animals Cells Cultured Base Sequence Molecular biology Herpesvirus 1 Suid Blotting Southern chemistry Chromosome Inversion DNA Viral Mutation DNA Plasmids |
| Zdroj: | Virology. 187(1) |
| ISSN: | 0042-6822 |
| Popis: | When pseudorabies virus (PrV) strains are grown in chicken embryo fibroblasts (CEF), variants (“translocation” mutants) arise in which there is a duplication of the leftmost sequences of the genome and their translocation in inverted orientation next to the internal inverted repeat bracketing the S component. In these variants, the U L becomes bracketed by inverted repeats and is found in two orientations relative to the U S . To study the cis -functions involved in cleavage of concatemeric DNA as well as those involved in inversion of the L component and to ascertain whether the two events are linked in the “translocation” mutants, a viral mutant (vLD68) was constructed in which the terminal 64 bp of the L component (that include sequences with homology to the pac 2 site of HSV) and the 4 terminal by of the S component were deleted from the internal junction. Although revenants that have acquired the 68 by at the internal junction emerge rapidly in populations of vLD68, analysis of the characteristics of this mutant revealed that: (1) the termini derived from both orientations of the L component include the 64 by that have been deleted from the internal junction of vLD68; (2) in contrast to other “translocation” mutants, the internal junction of the vLD68 genome is not a good substrate for cleavage; (3) inversion of the L component of true vLD68 DNA does not occur or is rare; a good correlation exists in the populations of vLD68 between the proportion of revertants that have acquired an intact internal junction and the proportion of genomes with an L component that inverts. These results show that an intact internal junction in “translocation” mutants is necessary for both inversion of their L components and cleavage at their alternative internal junction. Since cleavage at the alternative junction will result in inversion of the L component, we conclude that inversion of the L component of “translocation” mutants of PrV can be attributed to cleavage of concatemeric DNA at the internal alternative junction. |
| Databáze: | OpenAIRE |
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