A role for reverse transcripts in gene conversion

  title={A role for reverse transcripts in gene conversion},
  author={Leslie Derr and Jeffrey N. Strathern},
RECOMBINATION between a diffusible reverse transcript and its homologous chromosomal allele has been proposed as a mechanism for the precise removal of introns from DNA and gene conversion of dispersed repeated sequences1,2. We have reported that RNA-mediated recombination occurs in the yeast Saccharomyces cerevisiae3. This recombination requires expression of the retrotransposon Ty, and results in intron loss from a plasmid-borne marker gene and the formation of pseudogenes. Because the… 
The involvement of cellular recombination and repair genes in RNA-mediated recombination in Saccharomyces cerevisiae.
It is found that mutation of the mitotic RecA homologs RAD51, RAD55, and RAD57 increases the rate of RNA-mediated recombination relative to the wild type, and that these gene functions are not required for RNA- mediated gene conversion.
Retrosequence formation restructures the yeast genome.
It is reported that Ty1-dependent formation of retrosequences derived from single-copy gene transcripts is progressively elevated as yeast cells senesce in the absence of telomerase, supporting a role for reverse transcripts in promoting chromosome rearrangements.
Efficient homologous recombination of Ty1 element cDNA when integration is blocked.
Ty1 cDNA is utilized much more efficiently for homologous recombination when IN-mediated integration is blocked, and multimeric insertions occurred without altering the levels of total Ty1 RNA, virus-like particle-associated RNA or cDNA, Ty1 capsid proteins, or IN.
Retrotransposon reverse-transcriptase-mediated repair of chromosomal breaks
It is shown that DSBs can be fixed by the insertion of complementary DNAs at the break site, and this data support a role for endogenous retroelements in the repair of chromosomal breaks.
A mitochondrial retroplasmid integrates into mitochondrial DNA by a novel mechanism involving the synthesis of a hybrid cDNA and homologous recombination.
This analysis suggests that a simple integration mechanism involving template switching to generate a hybrid cDNA that integrates homologously could have been used by primitive retroelements prior to the acquisition of a specialized integration machinery.
Reverse transcription of spliced psbA mRNA in Chlamydomonas spp. and its possible role in evolutionary intron loss.
In vivo evidence is provided for reverse transcription of a physiologically important mRNA (psbA) in two naturally occurring species of Chlamydomonas that have also lost an intron from the same gene, possibly through recombination with the cDNA.
High frequency cDNA recombination of the saccharomyces retrotransposon Ty5: The LTR mediates formation of tandem elements.
It is proposed that recombination is initiated between the LTRs of the cDNA and substrate and that internal sequences promote tandem element formation by facilitating sequence alignment.
Transcript RNA supports precise repair of its own DNA gene
It is found that transcript RNA is more efficient in repairing a DSB in its own DNA than in a homologous but ectopic locus (in trans), and an antagonistic role of RNase H in RNA-DNA recombination is highlighted.
RNA-templated DNA repair
It is shown here thatRNA can serve as a template for DNA synthesis during repair of a chromosomal DSB in yeast, and the observation that even yeast replicative DNA polymerases such as α and δ can copy short RNA template tracts in vitro demonstrate that RNA can transfer genetic information in vivo through direct homologous interaction with chromosomal DNA.
DNA Recombination
Some general strategies to monitor a subset of the genomic instabilities: spontaneous mitotic recombination and chromosome loss, in both haploid and diploid cells are outlined.


A Method for Gene Disruption That Allows Repeated Use of URA3 Selection in the Construction of Multiply Disrupted Yeast Strains
An important feature of this 3.8-kb molecular construct that makes it especially useful is that recombination between the flanking direct repeats occurs at a high frequency (10-4) in vegetatively grown cultures.
Pseudogenes in yeast?
Nucleotide sequence and transcriptional mapping of the yeast pet56-his3-ded1 gene region.
A 1.8 kb region of chromosome XV containing the entire structural gene for the histidine biosynthetic enzyme imidazoleglycerolphosphate (IGP) dehydratase (his3) as well as the promoter sequences and 5'-proximal mRNA coding regions for the adjacent genes are characterized.
Retroviral vector system for the study of cDNA gene formation
Investigation of seven cDNA genes by Southern blot analysis revealed that all of them were truncated at either the 3' or the 5' end or both, raising the question of retroviral involvement in their formation.
The complete DNA sequence of yeast chromosome III
The entire DNA sequence of chromosome III of the yeast Saccharomyces cerevisiae has been determined. This is the first complete sequence analysis of an entire chromosome from any organism. The
Involvement of cDNA in homologous recombination between Ty elements in Saccharomyces cerevisiae.
Strains carrying a marked Ty element in the LYS2 locus were transformed with plasmids bearing a differently marked Ty1 element (Ty1Neo) under the control of the GAL promoter, showing homologous recombination with chromosomal copies of Ty elements.