scholarly journals Effects of Ty insertions on HIS4 transcription in Saccharomyces cerevisiae.

1984 ◽  
Vol 4 (7) ◽  
pp. 1246-1251 ◽  
Author(s):  
S J Silverman ◽  
G R Fink
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Regulatory Region ◽  
Initiation Site ◽  
Suppressor Genes ◽  
Transcriptional Initiation ◽  
Ty Elements ◽  
Ty Element ◽  
Genetic Rearrangements

Insertion of two different Ty elements into the Saccharomyces cerevisiae HIS4 regulatory region eliminates transcription of HIS4. Transcription can be restored by genetic rearrangements involving the Ty element inserted at HIS4. Several deletions, an inversion, a translocation, and a gene conversion are capable of restoring HIS4 transcription. Some of the rearrangements result in new transcriptional initiation sites. One type of revertant of his4-912 results from recombination between the delta elements flanking the Ty element, leaving a solo delta in place of the complete Ty. Strains carrying a Ty912 delta at HIS4 are His- at 23 degrees C. Unlinked suppressors (SPT) lead to suppression of this His- phenotype and increase levels of the normal HIS4 transcript. These suppressor genes affect not only the amount of transcription from the normal HIS4 initiation site, but also that from new initiation sites within Ty sequences adjacent to HIS4.

Effects of Ty insertions on HIS4 transcription in Saccharomyces cerevisiae

1984 ◽  
Vol 4 (7) ◽  
pp. 1246-1251
Author(s):  
S J Silverman ◽  
G R Fink
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Regulatory Region ◽  
Initiation Site ◽  
Suppressor Genes ◽  
Transcriptional Initiation ◽  
Ty Elements ◽  
Ty Element ◽  
Genetic Rearrangements

Insertion of two different Ty elements into the Saccharomyces cerevisiae HIS4 regulatory region eliminates transcription of HIS4. Transcription can be restored by genetic rearrangements involving the Ty element inserted at HIS4. Several deletions, an inversion, a translocation, and a gene conversion are capable of restoring HIS4 transcription. Some of the rearrangements result in new transcriptional initiation sites. One type of revertant of his4-912 results from recombination between the delta elements flanking the Ty element, leaving a solo delta in place of the complete Ty. Strains carrying a Ty912 delta at HIS4 are His- at 23 degrees C. Unlinked suppressors (SPT) lead to suppression of this His- phenotype and increase levels of the normal HIS4 transcript. These suppressor genes affect not only the amount of transcription from the normal HIS4 initiation site, but also that from new initiation sites within Ty sequences adjacent to HIS4.

Meiotic recombination between repeated transposable elements in Saccharomyces cerevisiae

1988 ◽  
Vol 8 (7) ◽  
pp. 2942-2954
Author(s):  
M Kupiec ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transposable Elements ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
Small Region ◽  
Ty Elements ◽  
Ty Element ◽  
Reciprocal Exchange ◽  
Gene Conversions ◽  
Conversion Tract

We have measured the frequency of meiotic recombination between marked Ty elements in the Saccharomyces cerevisiae genome. These recombination events were usually nonreciprocal (gene conversions) and sometimes involved nonhomologous chromosomes. The frequency of ectopic gene conversion among Ty elements appeared lower than expected on the basis of previous studies of recombination between artificially constructed repeats. The conversion events involved either a subset of the total Ty elements in the genome or the conversion tract was restricted to a small region of the Ty element. In addition, the observed conversion events were very infrequently associated with reciprocal exchange.

Involvement of cDNA in homologous recombination between Ty elements in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (4) ◽  
pp. 1613-1620
Author(s):  
C Melamed ◽  
Y Nevo ◽  
M Kupiec
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Homologous Recombination ◽  
Reverse Transcriptase ◽  
Gene Conversion ◽  
Reverse Transcription ◽  
Repeated Sequences ◽  
Homologous Gene ◽  
Ty Elements ◽  
Low Level ◽  
Ty Element

Strains carrying a marked Ty element (TyUra) in the LYS2 locus were transformed with plasmids bearing a differently marked Ty1 element (Ty1Neo) under the control of the GAL promoter. When these strains were grown in glucose, a low level of gene conversion events involving TyUra was detected. Upon growth on galactose an increase in the rate of gene conversion was seen. This homologous recombination is not the consequence of increased levels of transposition. When an intron-containing fragment was inserted into Ty1Neo, some of the convertants had the intron removed, implying an RNA intermediate. Mutations that affect reverse transcriptase or reverse transcription of Ty1Neo greatly reduce the induction of recombination in galactose. Thus, Ty cDNA is involved in homologous gene conversion with chromosomal copies of Ty elements. Our results have implications about the way families of repeated sequences retain homogeneity throughout evolution.

scholarly journals Involvement of cDNA in homologous recombination between Ty elements in Saccharomyces cerevisiae.

1992 ◽  
Vol 12 (4) ◽  
pp. 1613-1620 ◽  
Author(s):  
C Melamed ◽  
Y Nevo ◽  
M Kupiec
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Homologous Recombination ◽  
Reverse Transcriptase ◽  
Gene Conversion ◽  
Reverse Transcription ◽  
Repeated Sequences ◽  
Homologous Gene ◽  
Ty Elements ◽  
Low Level ◽  
Ty Element

Strains carrying a marked Ty element (TyUra) in the LYS2 locus were transformed with plasmids bearing a differently marked Ty1 element (Ty1Neo) under the control of the GAL promoter. When these strains were grown in glucose, a low level of gene conversion events involving TyUra was detected. Upon growth on galactose an increase in the rate of gene conversion was seen. This homologous recombination is not the consequence of increased levels of transposition. When an intron-containing fragment was inserted into Ty1Neo, some of the convertants had the intron removed, implying an RNA intermediate. Mutations that affect reverse transcriptase or reverse transcription of Ty1Neo greatly reduce the induction of recombination in galactose. Thus, Ty cDNA is involved in homologous gene conversion with chromosomal copies of Ty elements. Our results have implications about the way families of repeated sequences retain homogeneity throughout evolution.

scholarly journals Meiotic recombination between repeated transposable elements in Saccharomyces cerevisiae.

1988 ◽  
Vol 8 (7) ◽  
pp. 2942-2954 ◽  
Author(s):  
M Kupiec ◽  
T D Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transposable Elements ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
Small Region ◽  
Ty Elements ◽  
Ty Element ◽  
Reciprocal Exchange ◽  
Gene Conversions ◽  
Conversion Tract

We have measured the frequency of meiotic recombination between marked Ty elements in the Saccharomyces cerevisiae genome. These recombination events were usually nonreciprocal (gene conversions) and sometimes involved nonhomologous chromosomes. The frequency of ectopic gene conversion among Ty elements appeared lower than expected on the basis of previous studies of recombination between artificially constructed repeats. The conversion events involved either a subset of the total Ty elements in the genome or the conversion tract was restricted to a small region of the Ty element. In addition, the observed conversion events were very infrequently associated with reciprocal exchange.

scholarly journals Tempo and Mode of Ty Element Evolution in Saccharomyces cerevisiae

Genetics ◽  
1999 ◽  
Vol 151 (4) ◽  
pp. 1341-1351 ◽  
Author(s):  
I King Jordan ◽  
John F McDonald
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Negative Selection ◽  
Sequence Variation ◽  
Size Variation ◽  
Sequence Comparisons ◽  
Ty Elements ◽  
Ty Element ◽  
Amino Acid Sequence Variation ◽  
Element Evolution ◽  
High Level

Abstract The Saccharomyces cerevisiae genome contains five families of long terminal repeat (LTR) retrotransposons, Ty1–Ty5. The sequencing of the S. cerevisiae genome provides an unprecedented opportunity to examine the patterns of molecular variation existing among the entire genomic complement of Ty retrotransposons. We report the results of an analysis of the nucleotide and amino acid sequence variation within and between the five Ty element families of the S. cerevisiae genome. Our results indicate that individual Ty element families tend to be highly homogenous in both sequence and size variation. Comparisons of within-element 5′ and 3′ LTR sequences indicate that the vast majority of Ty elements have recently transposed. Furthermore, intrafamily Ty sequence comparisons reveal the action of negative selection on Ty element coding sequences. These results taken together suggest that there is a high level of genomic turnover of S. cerevisiae Ty elements, which is presumably in response to selective pressure to escape host-mediated repression and elimination mechanisms.

The Saccharomyces cerevisiae genome contains functional and nonfunctional copies of transposon Ty1

1988 ◽  
Vol 8 (4) ◽  
pp. 1432-1442 ◽  
Author(s):  
J D Boeke ◽  
D Eichinger ◽  
D Castrillon ◽  
G R Fink
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Long Terminal Repeat ◽  
Missense Mutation ◽  
Dna Sequence ◽  
Open Reading Frame ◽  
Yeast Genome ◽  
Reading Frame ◽  
Ty Elements ◽  
Ty Element ◽  
Repeat Sequences

Saccharomyces cerevisiae Ty elements are transposons closely related to retroviruses. The DNA sequence of a functional Ty element (TyH3) is presented. The long terminal repeat sequences are different, suggesting that TyH3 is a recombinant Ty element. A chromosomal Ty element near the LYS2 gene, Ty173, was found to be nonfunctional, even though it has no detectable insertions or deletions. The defect in Ty173 transposition is caused by a missense mutation giving rise to a Leu-to-Ile substitution in the TYB (pol) open reading frame. Several chromosomal Ty elements carry this lesion in their DNA, indicating that nonfunctional Ty elements are common in the yeast genome.

scholarly journals Sequences required for transcriptional initiation of the Saccharomyces cerevisiae CYC7 genes.

1987 ◽  
Vol 7 (10) ◽  
pp. 3785-3791 ◽  
Author(s):  
A M Healy ◽  
T L Helser ◽  
R S Zitomer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Spatial Relationship ◽  
Initiation Site ◽  
Tata Box ◽  
Upstream Region ◽  
Base Pairs ◽  
Transcriptional Initiation ◽  
Consensus Sequences ◽  
Tata Sequence ◽  
Yeast Genes

A series of BAL 31 deletions were constructed in the upstream region of the Saccharomyces cerevisiae CYC7 gene to determine sequences required for transcriptional initiation. These deletions identified the TATA box as an alternating A-T sequence at -160 and the initiation sequences as well as the spatial relationship between them. The TATA box was necessary for wild-type levels of expression of the CYC7 gene. Decreasing the distance between the TATA sequence and the initiation site did not alter gene expression, but the site of transcription was shifted 3'-ward. In most cases, transcription initiated at a number of sites, the 5'-most of which was the first suitable site greater than 45 base pairs 3' of the TATA sequence, suggesting a spatial relationship between these sequences. Consensus sequences previously proposed for initiation sites were evaluated with respect to the start sites identified in this study as well as the start sites of other yeast genes.

Intrachromosomal movement of genetically marked Saccharomyces cerevisiae transposons by gene conversion

1984 ◽  
Vol 4 (4) ◽  
pp. 703-711
Author(s):  
G S Roeder ◽  
M Smith ◽  
E J Lambie
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Unique Sequence ◽  
Ura3 Gene ◽  
Ty Elements ◽  
Chromosome Iii

In this paper, we describe the movement of a genetically marked Saccharomyces cerevisiae transposon. Ty912(URA3), to new sites in the S. cerevisiae genome. Ty912 is an element present at the HIS4 locus in the his4-912 mutant. To detect movement of Ty912, this element has been genetically marked with the S. cerevisiae URA3 gene. Movement of Ty912(URA3) occurs by recombination between the marked element and homologous Ty elements elsewhere in the S. cerevisiae genome. Ty912(URA3) recombines most often with elements near the HIS4 locus on chromosome III, less often with Ty elements elsewhere on chromosome III, and least often with Ty elements on other chromosomes. These recombination events result in changes in the number of Ty elements present in the cell and in duplications and deletions of unique sequence DNA.

scholarly journals Intrachromosomal movement of genetically marked Saccharomyces cerevisiae transposons by gene conversion.

1984 ◽  
Vol 4 (4) ◽  
pp. 703-711 ◽  
Author(s):  
G S Roeder ◽  
M Smith ◽  
E J Lambie
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Unique Sequence ◽  
Ura3 Gene ◽  
Ty Elements ◽  
Chromosome Iii

In this paper, we describe the movement of a genetically marked Saccharomyces cerevisiae transposon. Ty912(URA3), to new sites in the S. cerevisiae genome. Ty912 is an element present at the HIS4 locus in the his4-912 mutant. To detect movement of Ty912, this element has been genetically marked with the S. cerevisiae URA3 gene. Movement of Ty912(URA3) occurs by recombination between the marked element and homologous Ty elements elsewhere in the S. cerevisiae genome. Ty912(URA3) recombines most often with elements near the HIS4 locus on chromosome III, less often with Ty elements elsewhere on chromosome III, and least often with Ty elements on other chromosomes. These recombination events result in changes in the number of Ty elements present in the cell and in duplications and deletions of unique sequence DNA.

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