scholarly journals RESOLUTION OF DICENTRIC CHROMOSOMES BY TY-MEDIATED RECOMBINATION IN YEAST

Genetics ◽  
1985 ◽  
Vol 110 (3) ◽  
pp. 397-419
Author(s):  
Richard T Surosky ◽  
Bik-Kwoon Tye
Keyword(s):  
Centromeric Region ◽  
Ring Chromosome ◽  
Normal Chromosome ◽  
Meiotic Segregation ◽  
Linear Chromosome ◽  
Ty Elements ◽  
Dicentric Chromosomes ◽  
Chromosome Iii ◽  
The Right ◽  
Diploid Cells

ABSTRACT We have integrated a plasmid containing a yeast centromere, CEN5, into the HIS4 region of chromosome III by transformation. Of the three transformant colonies examined, none contained a dicentric chromosome, but all contained a rearranged chromosome III. In one transformant, rearrangement occurred by homologous recombination between two Ty elements; one on the left arm and the other on the right arm of chromosome III. This event produced a ring chromosome (ring chromosome III) of about 60 kb consisting of CEN3 and all other sequences between the two Ty elements. In addition, a linear chromosome (chromosome IIIA) consisting of sequences distal to the two Ty elements including CEN5, but lacking 60 kb of sequences from the centromeric region, was produced. Two other transformants also contain a similarly altered linear chromosome III as well as an apparently normal copy of chromosome III. These results suggest that dicentric chromosomes cannot be maintained in yeast and that dicentric structures must be resolved for the cell to survive.—The meiotic segregation properties of ring chromosome III and linear chromosome IIIA were examined in diploid cells which also contained a normal chromosome III. Chromosome IIIA and normal chromosome III disjoined normally, indicating that homology or parallel location of the centromeric regions of these chromosomes are not essential for proper meiotic segregation. In contrast, the 60-kb ring chromosome III, which is homologous to the centromeric region of the normal chromosome III, did not appear to pair with fidelity with chromosome III.

scholarly journals MEIOTIC AND MITOTIC BEHAVIOR OF DICENTRIC CHROMOSOMES IN SACCHAROMYCES CEREVISIAE

Genetics ◽  
1984 ◽  
Vol 106 (2) ◽  
pp. 185-205
Author(s):  
James E Haber ◽  
Patricia C Thorburn ◽  
David Rogers
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Recombinant Dna ◽  
Ring Chromosome ◽  
Dicentric Chromosome ◽  
Linear Chromosome ◽  
Dicentric Chromosomes ◽  
Ring Chromosomes ◽  
Mitotic Instability ◽  
Unequal Number ◽  
Chromosome Iii

ABSTRACT Meiotic recombination between a circular and a linear chromosome in Saccharomyces cerevisiae has been investigated. The circle was a haploid-viable derivative of chromosome III constructed by joining regions near the two chromosome ends via a recombinant DNA construction: (HMR/MAT-URA3-pBR322-MAT/HML) and was also deleted for MAL2(which therefore uniquely marks a linear chromosome III). Recombination along chromosome III was measured for eight intervals spanning the entire length of the circular derivative. Only 25% of all tetrads from a ring/rod diploid contained four viable spores. These proved to be cases in which there was either no recombination along chromosome III or in which there were two-strand double crossovers or higher order crossovers that would not produce a dicentric chromosome.—At least half of the tetrads with three viable spores included one Ura+ Mal+ spore that was genetically highly unstable. The Ura+ Mal+ spore colonies gave rise to as many as seven genetically distinct, stable ("healed") derivatives, some of which had lost either URA3 or MAL2. Analysis of markers on chromosome III suggests that dicentric chromosomes frequently do not break during meiosis but are inherited intact into a haploid spore. In mitosis, however, the dicentric chromosome is frequently broken, giving rise to a variety of genetically distinct derivatives. We have also shown that dicentric ring chromosomes exhibit similar behavior: at least half the time they are not broken during meiosis but are broken and healed during mitosis.—The ring/rod diploid can also be used to determine the frequency of sister chromatid exchange (SCE) along an entire yeast ring chromosome. We estimate that an unequal number of SCE events occurs in approximately 15% of all cells undergoing meiosis. In contrast, the mitotic instability (and presumably SCE events) of a ring chromosome is low, occurring at a rate of about 1.2 x 10-3 per cell division.

The complete sequence of a 10·8kb fragment to the right of the chromosome III centromere ofSaccharomyces cerevisiae

Yeast ◽  
1992 ◽  
Vol 8 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Nicolas Biteau ◽  
Christophe Fremaux ◽  
Sylvie Hebrard ◽  
Annie Menara ◽  
Michael Aigle ◽  
...  
Keyword(s):  
Complete Sequence ◽  
Chromosome Iii ◽  
The Right

The effect on chromosome stability of deleting replication origins

1993 ◽  
Vol 13 (1) ◽  
pp. 391-398
Author(s):  
A Dershowitz ◽  
C S Newlon
Keyword(s):  
Ring Chromosome ◽  
High Rate ◽  
Chromosome Stability ◽  
Replication Origins ◽  
Chromosomal Dna ◽  
Circular Chromosome ◽  
Cell Cycles ◽  
Highly Active ◽  
Dna Replication Origins ◽  
Chromosome Iii

The observed spacing between chromosomal DNA replication origins in Saccharomyces cerevisiae is at least four times shorter than should be necessary to ensure complete replication of chromosomal DNA during the S phase. To test whether all replication origins are required for normal chromosome stability, the loss rates of derivatives of chromosome III from which one or more origins had been deleted were measured. In the case of a 61-kb circular derivative of the chromosome that has two highly active origins and one origin that initiates only 10 to 20% of the time, deletion of either highly active origin increased its rate of loss two- to fourfold. Deletion of both highly active origins caused the ring chromosome to be lost in approximately 20% of cell divisions. This very high rate of loss demonstrates that there are no efficient cryptic origins on the ring chromosome that are capable of ensuring its replication in the absence of the origins that are normally used. Deletion of the same two origins from the full-length chromosome III, which contains more than six replication origins, had no effect on its rate of loss. These results suggest that the increase in the rate of loss of the small circular chromosome from which a single highly active origin was deleted was caused by the failure of the remaining highly active origin to initiate replication in a small fraction (approximately 0.003) of cell cycles.

scholarly journals TETRAPLOID STRAINS OF SACCHAROMYCES CEREVISIAE THAT ARE TRISOMIC FOR CHROMOSOME III

Genetics ◽  
1978 ◽  
Vol 89 (4) ◽  
pp. 667-684
Author(s):  
Michael I Riley ◽  
T R Manney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Computer Simulation ◽  
Meiotic Recombination ◽  
Meiotic Segregation ◽  
Segregation Data ◽  
Strong Interference ◽  
Chromosome Iii ◽  
Double Crossovers

ABSTRACT Meiotic segregation of several genes has been studied in tetraploid strains that are trisomic for chromosome III. The segregation data were compared to a computer simulation that assumes trivalent pairing of homologues involved in exchanges, followed by nonpreferential segregation. Trivalent pairing was characterized by higher frequencies of exchange as compared to bivalent pairing, and by the presence of spores resulting from at least double crossovers involving all three homologues. Trivalent segregation was characterized by a unique recombinant class. The strong interference normally exhibited in diploid meiotic recombination was not evident from the frequency of double crossovers in these strains.

scholarly journals MULTIPLE GENE SITES FOR 5S AND 18 + 28S RNA ON CHROMOSOMES OF GLYPTOTENDIPES BARBIPES (STAEGER)

1974 ◽  
Vol 62 (1) ◽  
pp. 132-144 ◽  
Author(s):  
Wu-Nan Wen ◽  
Pedro E. León ◽  
Donald R. Hague
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Nucleolar Organizer ◽  
Balbiani Ring ◽  
5S Rna ◽  
Multiple Gene ◽  
Main Site ◽  
Chromosome Iii ◽  
The Right

Ribosomal RNAs (28 + 18S and 5S) and 4S RNA extracted from the chironomid Glyptotendipes barbipes were iodinated in vitro with 125I and hybridized to the salivary gland chromosomes of G. barbipes and Drosophila melanogaster. Iodinated 18 + 28 S RNA labeled three puffed sites with associated nucleoli on chromosomes IR, IIL, and IIIL of G. barbipes and the nucleolar organizer of Drosophila. Labeled 5S RNA hybridized to three sites on chromosome IIIR, two sites on chromosome IIR and one site in a Balbiani ring on chromosome IV of Glyptotendipes. Most of the label produced by this RNA was localized seven bands away from the centromere on the right arm of chromosome III, and we consider this to be the main site complementary to 5S RNA in the chironomid. This same RNA preparation specifically labeled the 56 EF region of chromosome IIR of Drosophila which has been shown previously to be the only site labeled when hybridized with homologous 5S RNA. Hybridization of G. barbipes chromosomes with iodinated 4S RNA produced no clearly localized labeled sites over the exposure periods studied.

scholarly journals The effect on chromosome stability of deleting replication origins.

1993 ◽  
Vol 13 (1) ◽  
pp. 391-398 ◽  
Author(s):  
A Dershowitz ◽  
C S Newlon
Keyword(s):  
Ring Chromosome ◽  
High Rate ◽  
Chromosome Stability ◽  
Replication Origins ◽  
Chromosomal Dna ◽  
Circular Chromosome ◽  
Cell Cycles ◽  
Highly Active ◽  
Dna Replication Origins ◽  
Chromosome Iii

The observed spacing between chromosomal DNA replication origins in Saccharomyces cerevisiae is at least four times shorter than should be necessary to ensure complete replication of chromosomal DNA during the S phase. To test whether all replication origins are required for normal chromosome stability, the loss rates of derivatives of chromosome III from which one or more origins had been deleted were measured. In the case of a 61-kb circular derivative of the chromosome that has two highly active origins and one origin that initiates only 10 to 20% of the time, deletion of either highly active origin increased its rate of loss two- to fourfold. Deletion of both highly active origins caused the ring chromosome to be lost in approximately 20% of cell divisions. This very high rate of loss demonstrates that there are no efficient cryptic origins on the ring chromosome that are capable of ensuring its replication in the absence of the origins that are normally used. Deletion of the same two origins from the full-length chromosome III, which contains more than six replication origins, had no effect on its rate of loss. These results suggest that the increase in the rate of loss of the small circular chromosome from which a single highly active origin was deleted was caused by the failure of the remaining highly active origin to initiate replication in a small fraction (approximately 0.003) of cell cycles.

scholarly journals Isolation and genetic analysis of Saccharomyces cerevisiae mutants supersensitive to G1 arrest by a factor and alpha factor pheromones.

1982 ◽  
Vol 2 (1) ◽  
pp. 11-20 ◽  
Author(s):  
R K Chan ◽  
C A Otte
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Solid Medium ◽  
G1 Arrest ◽  
Alpha Cells ◽  
Opposite Mating Type ◽  
Alpha Factor ◽  
Complementation Groups ◽  
Chromosome Iii ◽  
The Right

Eight independently isolated mutants which are supersensitive (Sst-) to the G1 arrest induced by the tridecapeptide pheromone alpha factor were identified by screening mutagenized Saccharomyces cerevisiae MATa cells on solid medium for increased growth inhibition by alpha factor. These mutants carried lesions in two complementation groups, sst1 and sst2. Mutations at the sst1 locus were mating type specific: MATa sst1 cells were supersensitive to alpha factor, but MAT alpha sst1 cells were not supersensitive to a factor. In contrast, mutations at the sst2 locus conferred supersensitivity to the pheromones of the opposite mating type on both MATa and MAT alpha cells. Even in the absence of added alpha pheromone, about 10% of the cells in exponentially growing cultures of MATa strains carrying any of three different alleles of sst2 (including the ochre mutation sst2-4) had the aberrant morphology ("shmoo" shape) that normally develops only after MATa cells are exposed to alpha factor. This "self-shmooing" phenotype was genetically linked to the sst2 mutations, although the leakiest allele isolated (sst2-3) did not display this characteristic. Normal MATa/MAT alpha diploids do not respond to pheromones; diploids homozygous for an sst2 mutation (MATa/MAT alpha sst2-1/sst2-1) were still insensitive to alpha factor. The sst1 gene was mapped to within 6.9 centimorgans of his6 on chromosome IX. The sst2 gene was unlinked to sst1, was not centromere linked, and was shown to be neither linked to nor centromere distal to MAT on the right arm of chromosome III.

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