DNA fragments isolated from the left end of chromosome III in yeast are repaired to generate functional telomeres

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 758-765
Author(s):  
Linda L. Button ◽  
Caroline R. Astell

DNA fragments isolated from the left end of chromosome III in the yeast Saccharomyces cerevisiae are recognized as telomeres in yeast, since plasmids constructed with such fragments are replicated as linear molecules in yeast. The fragments have a 1.18-kb region homologous with the type X regions at yeast telomeres that contain ARS elements that allow the autonomous replication of plasmids in yeast. The X region contains a functional ARS element including the ARS consensus sequence and a distal 200-bp region that enhances ARS function. Distal to the type X region, the fragments have a region of tandemly repeated DNA sequence defined by the formula 5′-C1–3A-3′, and designated as the T region at yeast telomeres. Although the terminus of the chromosome was removed in the procedure used to molecularly isolate the left end of chromosome III, the fragments containing the X and T region are recognized as chromosome ends in yeast. Plasmids with inverted repeats of the chromosome III end fragments are resolved in yeast to produce linear plasmids with telomeres that are similar in length and heterogeneity with the natural left end on chromosome III. Fragments with progressive deletions from the distal end of chromosome III were prepared and used to study the X – T region requirements for distinguishing the fragments as telomeres in yeast.Key words: yeast, S. cerevisiae, functional telomere, linear plasmids.

1987 ◽  
Vol 7 (1) ◽  
pp. 68-75 ◽  
Author(s):  
A Gaudet ◽  
M Fitzgerald-Hayes

Centromere DNA from 11 of the 16 chromosomes of the yeast Saccharomyces cerevisiae have been analyzed and reveal three sequence elements common to each centromere, referred to as conserved centromere DNA elements (CDE). The adenine-plus-thymine (A + T)-rich central core element, CDE II, is flanked by two short conserved sequences, CDE I (8 base pairs [bp]) and CDE III (25 bp). Although no consensus sequence exists among the different CDE II regions, they do have three common features of sequence organization. First, the CDE II regions are similar in length, ranging from 78 to 86 bp measured from CDE I to the left boundary of CDE III. Second, the base composition is always greater than 90% A + T. Finally, the A and T residues in these segments are often arranged in runs of A and runs of T residues, sometimes with six or seven bases in a stretch. We constructed insertion, deletion, and replacement mutations in the CDE II region of the centromere from chromosome III, CEN3, designed to investigate the length and sequence requirements for function of the CDE II region of the centromere. We analyzed the effect of these altered centromeres on plasmid and chromosome segregation in S. cerevisiae. Our results show that increasing the length of CDE II from 84 to 154 bp causes a 100-fold increase in chromosome nondisjunction. Deletion mutations removing segments of the A + T-rich CDE II DNA also cause aberrant segregation. In some cases partial function could be restored by replacing the deleted DNA with fragments whose primary sequence or base composition is very different from that of the wild-type CDE II DNA. In addition, we found that identical mutations introduced into different positions in CDE II have very similar effects.


1994 ◽  
Vol 14 (5) ◽  
pp. 3524-3534
Author(s):  
I Collins ◽  
C S Newlon

Autonomously replicating sequence (ARS) elements are identified by their ability to promote high-frequency transformation and extrachromosomal replication of plasmids in the yeast Saccharomyces cerevisiae. Six of the 14 ARS elements present in a 200-kb region of Saccharomyces cerevisiae chromosome III are mitotic chromosomal replication origins. The unexpected observation that eight ARS elements do not function at detectable levels as chromosomal replication origins during mitotic growth suggested that these ARS elements may function as chromosomal origins during premeiotic S phase. Two-dimensional agarose gel electrophoresis was used to map premeiotic replication origins in a 100-kb segment of chromosome III between HML and CEN3. The pattern of origin usage in premeiotic S phase was identical to that in mitotic S phase, with the possible exception of ARS308, which is an inefficient mitotic origin associated with CEN3. CEN3 was found to replicate during premeiotic S phase, demonstrating that the failure of sister chromatids to disjoin during the meiosis I division is not due to unreplicated centromeres. No origins were found in the DNA fragments without ARS function. Thus, in both mitosis and meiosis, chromosomal replication origins are coincident with ARS elements but not all ARS elements have chromosomal origin function. The efficiency of origin use and the patterns of replication termination are similar in meiosis and in mitosis. DNA replication termination occurs over a broad distance between active origins.


1994 ◽  
Vol 14 (5) ◽  
pp. 3524-3534 ◽  
Author(s):  
I Collins ◽  
C S Newlon

Autonomously replicating sequence (ARS) elements are identified by their ability to promote high-frequency transformation and extrachromosomal replication of plasmids in the yeast Saccharomyces cerevisiae. Six of the 14 ARS elements present in a 200-kb region of Saccharomyces cerevisiae chromosome III are mitotic chromosomal replication origins. The unexpected observation that eight ARS elements do not function at detectable levels as chromosomal replication origins during mitotic growth suggested that these ARS elements may function as chromosomal origins during premeiotic S phase. Two-dimensional agarose gel electrophoresis was used to map premeiotic replication origins in a 100-kb segment of chromosome III between HML and CEN3. The pattern of origin usage in premeiotic S phase was identical to that in mitotic S phase, with the possible exception of ARS308, which is an inefficient mitotic origin associated with CEN3. CEN3 was found to replicate during premeiotic S phase, demonstrating that the failure of sister chromatids to disjoin during the meiosis I division is not due to unreplicated centromeres. No origins were found in the DNA fragments without ARS function. Thus, in both mitosis and meiosis, chromosomal replication origins are coincident with ARS elements but not all ARS elements have chromosomal origin function. The efficiency of origin use and the patterns of replication termination are similar in meiosis and in mitosis. DNA replication termination occurs over a broad distance between active origins.


2008 ◽  
Vol 28 (16) ◽  
pp. 5071-5081 ◽  
Author(s):  
FuJung Chang ◽  
James F. Theis ◽  
Jeremy Miller ◽  
Conrad A. Nieduszynski ◽  
Carol S. Newlon ◽  
...  

ABSTRACT Saccharomyces cerevisiae chromosome III encodes 11 autonomously replicating sequence (ARS) elements that function as chromosomal replicators. The essential 11-bp ARS consensus sequence (ACS) that binds the origin recognition complex (ORC) has been experimentally defined for most of these replicators but not for ARS318 (HMR-I), which is one of the HMR silencers. In this study, we performed a comprehensive linker scan analysis of ARS318. Unexpectedly, this replicator depends on a 9/11-bp match to the ACS that positions the ORC binding site only 6 bp away from an Abf1p binding site. Although a largely inactive replicator on the chromosome, ARS318 becomes active if the nearby HMR-E silencer is deleted. We also performed a multiple sequence alignment of confirmed replicators on chromosomes III, VI, and VII. This analysis revealed a highly conserved WTW motif 17 to 19 bp from the ACS that is functionally important and is apparent in the 228 phylogenetically conserved ARS elements among the six sensu stricto Saccharomyces species.


1987 ◽  
Vol 7 (1) ◽  
pp. 68-75
Author(s):  
A Gaudet ◽  
M Fitzgerald-Hayes

Centromere DNA from 11 of the 16 chromosomes of the yeast Saccharomyces cerevisiae have been analyzed and reveal three sequence elements common to each centromere, referred to as conserved centromere DNA elements (CDE). The adenine-plus-thymine (A + T)-rich central core element, CDE II, is flanked by two short conserved sequences, CDE I (8 base pairs [bp]) and CDE III (25 bp). Although no consensus sequence exists among the different CDE II regions, they do have three common features of sequence organization. First, the CDE II regions are similar in length, ranging from 78 to 86 bp measured from CDE I to the left boundary of CDE III. Second, the base composition is always greater than 90% A + T. Finally, the A and T residues in these segments are often arranged in runs of A and runs of T residues, sometimes with six or seven bases in a stretch. We constructed insertion, deletion, and replacement mutations in the CDE II region of the centromere from chromosome III, CEN3, designed to investigate the length and sequence requirements for function of the CDE II region of the centromere. We analyzed the effect of these altered centromeres on plasmid and chromosome segregation in S. cerevisiae. Our results show that increasing the length of CDE II from 84 to 154 bp causes a 100-fold increase in chromosome nondisjunction. Deletion mutations removing segments of the A + T-rich CDE II DNA also cause aberrant segregation. In some cases partial function could be restored by replacing the deleted DNA with fragments whose primary sequence or base composition is very different from that of the wild-type CDE II DNA. In addition, we found that identical mutations introduced into different positions in CDE II have very similar effects.


Genetics ◽  
1989 ◽  
Vol 123 (1) ◽  
pp. 81-95 ◽  
Author(s):  
E J Louis ◽  
J E Haber

Abstract The presence of the tRNA ochre suppressors SUP11 and SUP5 is found to induce meiosis I nondisjunction in the yeast Saccharomyces cerevisiae. The induction increases with increasing dosage of the suppressor and decreases in the presence of an antisuppressor. The effect is independent of the chromosomal location of SUP11. Each of five different chromosomes monitored exhibited nondisjunction at frequencies of 0.1%-1.1% of random spores, which is a 16-160-fold increase over wild-type levels. Increased nondisjunction is reflected by a marked increase in tetrads with two and zero viable spores. In the case of chromosome III, for which a 50-cM map interval was monitored, the resulting disomes are all in the parental nonrecombinant configuration. Recombination along chromosome III appears normal both in meioses that have no nondisjunction and in meioses for which there was nondisjunction of another chromosome. We propose that a proportion of one or more proteins involved in chromosome pairing, recombination or segregation are aberrant due to translational read-through of the normal ochre stop codon. Hygromycin B, an antibiotic that can suppress nonsense mutations via translational read-through, also induces nonrecombinant meiosis I nondisjunction. Increases in mistranslation, therefore, increase the production of aneuploids during meiosis. There was no observable effect of SUP11 on mitotic chromosome nondisjunction; however some disomes caused SUP11 ade2-ochre strains to appear white or red, instead of pink.


2001 ◽  
Vol 12 (11) ◽  
pp. 3317-3327 ◽  
Author(s):  
Arkadi Poloumienko ◽  
Ann Dershowitz ◽  
Jitakshi De ◽  
Carol S. Newlon

In Saccharomyces cerevisiae chromosomal DNA replication initiates at intervals of ∼40 kb and depends upon the activity of autonomously replicating sequence (ARS) elements. The identification of ARS elements and analysis of their function as chromosomal replication origins requires the use of functional assays because they are not sufficiently similar to identify by DNA sequence analysis. To complete the systematic identification of ARS elements onS. cerevisiae chromosome III, overlapping clones covering 140 kb of the right arm were tested for their ability to promote extrachromosomal maintenance of plasmids. Examination of chromosomal replication intermediates of each of the seven ARS elements identified revealed that their efficiencies of use as chromosomal replication origins varied widely, with four ARS elements active in ≤10% of cells in the population and two ARS elements active in ≥90% of the population. Together with our previous analysis of a 200-kb region of chromosome III, these data provide the first complete analysis of ARS elements and DNA replication origins on an entire eukaryotic chromosome.


1988 ◽  
Vol 8 (2) ◽  
pp. 595-604
Author(s):  
L S Symington ◽  
T D Petes

To examine the relationship between genetic and physical chromosome maps, we constructed a diploid strain of the yeast Saccharomyces cerevisiae heterozygous for 12 restriction site mutations within a 23-kilobase (5-centimorgan) interval of chromosome III. Crossovers were not uniformly distributed along the chromosome, one interval containing significantly more and one interval significantly fewer crossovers than expected. One-third of these crossovers occurred within 6 kilobases of the centromere. Approximately half of the exchanges were associated with gene conversion events. The minimum length of gene conversion tracts varied from 4 base pairs to more than 12 kilobases, and these tracts were nonuniformly distributed along the chromosome. We conclude that the chromosomal sequence or structure has a dramatic effect on meiotic recombination.


1994 ◽  
Vol 14 (11) ◽  
pp. 7652-7659
Author(s):  
J F Theis ◽  
C S Newlon

ARS307 is highly active as a replication origin in its native location on chromosome III of Saccharomyces cerevisiae. Its ability to confer autonomous replication activity on plasmids requires the presence of an 11-bp autonomously replicating sequence (ARS) consensus sequence (ACS), which is also required for chromosomal origin function, as well as approximately 100 bp of sequence flanking the ACS called domain B. To further define the sequences required for ARS function, a linker substitution mutagenesis of domain B was carried out. The mutations defined two sequences, B1 and B2, that contribute to ARS activity. Therefore, like ARS1, domain B of ARS307 is composed of functional subdomains. Constructs carrying mutations in the B1 element were used to replace the chromosomal copy of ARS307. These mutations caused a reduction in chromosomal origin activity, demonstrating that the B1 element is required for efficient chromosomal origin function.


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