The Chromosome Transmission Fidelity Assay for Measuring Chromosome Loss in Yeast

ABSTRACT Thirteen of 14 temperature-sensitive mutants deficient in successive steps of mitotic chromosome transmission (cdc2, 4, 5, 6, 7, 8, 9, 13, 14, 15, 16, 17 and 20) from spindle pole body separation to a late stage of nuclear division exhibited a dramatic increase in the frequency of chromosome loss and/or mitotic recombination when they were grown at their maximum permissive temperatures. The increase in chromosome loss and/or recombination is likely to be due to the deficiency of functional gene product rather than to an aberrant function of the mutant gene product since the mutant alleles are, with one exception, recessive to the wild-type allele for this phenotype. The generality of this result suggests that a delay in almost any stage of chromosome replication or segregation leads to a decrease in the fidelity of mitotic chromosome transmission. In contrast, temperature-sensitive mutants defective in the control step of the cell cycle (cdc28), in cytokinesis (cdc3) or in protein synthesis (ils1) did not exhibit increased recombination or chromosome loss.—Based upon previous results with mutants and DNA-damaging agents in a variety of organisms, we suggest that the induction of mitotic recombination in certain mutants is due to the action of a repair pathway upon nicks or gaps left in the DNA. This interpretation is supported by the fact that the induced recombination is dependent upon the RAD52 gene product, an essential component in the recombinogenic DNA repair pathway. Gene products whose deficiency leads to induced recombination are, therefore, strong candidates for proteins that function in DNA metabolism. Among the mutants that induce recombination are those known to be defective in some aspect of DNA replication (cdc2, 6, 8, 9) as well as some mutants defective in the G2 (cdc13 and 17) and M (cdc5 and 14) phases of the mitotic cycle. We suggest that special aspects of DNA metabolism may be occurring in G2 and M in order to prepare the chromosomes for proper segregation.

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A novel histone H4 mutant defective in nuclear division and mitotic chromosome transmission.

Molecular and Cellular Biology ◽

10.1128/mcb.16.3.1017 ◽

1996 ◽

Vol 16 (3) ◽

pp. 1017-1026 ◽

Cited By ~ 52

Author(s):

M M Smith ◽

P Yang ◽

M S Santisteban ◽

P W Boone ◽

A T Goldstein ◽

...

Keyword(s):

Mitotic Chromosome ◽

Nuclear Division ◽

Dna Recombination ◽

Chromosome Loss ◽

Temperature Sensitive ◽

Restrictive Temperature ◽

Histone H4 ◽

Eukaryotic Chromosome ◽

Chromosome Transmission

The histone proteins are essential for the assembly and function of th e eukaryotic chromosome. Here we report the first isolation of a temperature-sensitive lethal histone H4 mutant defective in mitotic chromosome transmission Saccharomyces cerevisiae. The mutant requires two amino acid substitutions in histone H4: a lethal Thr-to-Ile change at position 82, which lies within one of the DNA-binding surfaces of the protein, and a substitution of Ala to Val at position 89 that is an intragenic suppressor. Genetic and biochemical evidence shows that the mutant histone H4 is temperature sensitive for function but not for synthesis, deposition, or stability. The chromatin structure of 2 micrometer circle minichromosomes is temperature sensitive in vivo, consistent with a defect in H4-DNA interactions. The mutant also has defects in transcription, displaying weak Spt- phenotypes. At the restrictive temperature, mutant cells arrest in the cell cycle at nuclear division, with a large bud, a single nucleus with 2C DNA content, and a short bipolar spindle. At semipermissive temperatures, the frequency of chromosome loss is elevated 60-fold in the mutant while DNA recombination frequencies are unaffected. High-copy CSE4, encoding an H3 variant related to the mammalian CENP-A kinetochore antigen, was found to suppress the temperature sensitivity of the mutant without suppressing the Spt- transcription defect. These genetic, biochemical, and phenotypic results indicate that this novel histone H4 mutant defines one or more chromatin-dependent steps in chromosome segregation.

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Mutant alleles of the meiotic locus, mei-9, differ in degree of effects on rod chromosome magnification and ring chromosome transmission in Drosophila

Genetics Research ◽

10.1017/s0016672300028111 ◽

1989 ◽

Vol 53 (3) ◽

pp. 155-161 ◽

Cited By ~ 1

Author(s):

Donald J. Komma ◽

Heath Graves ◽

Sharyn A. Endow

Keyword(s):

Excision Repair ◽

Ring Chromosome ◽

Inhibitory Effect ◽

Ribosomal Gene ◽

Chromosome Loss ◽

Repair Pathway ◽

Chromosome Transmission ◽

Ring Chromosomes ◽

Allele Specific

SummaryTwo mutant alleles of the meiotic locus, mei-9, have been examined for their effect on magnification of a rod Xbb chromosome and transmission of a ring Xbb chromosome under magnifying conditions. Our results indicate that the effects of these two mutations are allele-specific: mei-9a strongly inhibits both rod chromosome magnification and ring chromosome loss under magnifying conditions, while mei-9b has a smaller inhibitory effect on rod chromosome magnification and on the transmission of ring chromosomes under magnifying conditions. These observations can be explained by a difference in leakiness between the two alleles. Our results demonstrate that mutants defective in excision repair and repair replication inhibit ribosomal gene magnification. This suggests that a component of the excision repair pathway is involved in the process of magnification.

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Analysis of Primary Structural Determinants That Distinguish the Centromere-Specific Function of Histone Variant Cse4p from Histone H3

Molecular and Cellular Biology ◽

10.1128/mcb.19.9.6130 ◽

1999 ◽

Vol 19 (9) ◽

pp. 6130-6139 ◽

Cited By ~ 59

Author(s):

Kevin C. Keith ◽

Richard E. Baker ◽

Yinhuai Chen ◽

Kendra Harris ◽

Sam Stoler ◽

...

Keyword(s):

Mutational Analysis ◽

Histone H3 ◽

Biochemical Properties ◽

Chromosome Loss ◽

Structural Determinants ◽

Histone Fold ◽

Chromosome Transmission ◽

Histone Fold Domain ◽

N Terminus ◽

Nested Deletions

ABSTRACT Cse4p is a variant of histone H3 that has an essential role in chromosome segregation and centromere chromatin structure in budding yeast. Cse4p has a unique 135-amino-acid N terminus and a C-terminal histone-fold domain that is more than 60% identical to histone H3 and the mammalian centromere protein CENP-A. Cse4p and CENP-A have biochemical properties similar to H3 and probably replace H3 in centromere-specific nucleosomes in yeasts and mammals, respectively. In order to identify regions of Cse4p that distinguish it from H3 and confer centromere function, a systematic site-directed mutational analysis was performed. Nested deletions of the Cse4p N terminus showed that this region of the protein contains at least one essential domain. The C-terminal histone-fold domain of Cse4p was analyzed by changing Cse4p amino acids that differ between Cse4p and H3 to the analogous H3 residues. Extensive substitution of contiguous Cse4p residues with H3 counterparts resulted in cell lethality. However, all large lethal substitution alleles could be subdivided into smaller viable alleles, many of which caused elevated rates of mitotic chromosome loss. The results indicate that residues critical for wild-type Cse4p function and high-fidelity chromosome transmission are distributed across the entire histone-fold domain. Our findings are discussed in the context of the known structure of H3 within the nucleosome and compared with previous results reported for CENP-A.

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GISH characterization of Erianthus arundinaceus chromosomes in three generations of sugarcane intergeneric hybrids

Genome ◽

10.1139/g10-010 ◽

2010 ◽

Vol 53 (5) ◽

pp. 331-336 ◽

Cited By ~ 36

Author(s):

Nathalie Piperidis ◽

Jian-wen Chen ◽

Hai-hua Deng ◽

Li-Ping Wang ◽

Phillip Jackson ◽

...

Keyword(s):

Saccharum Officinarum ◽

Intergeneric Hybrids ◽

Chromosome Loss ◽

Biotic And Abiotic Stresses ◽

Breeding Programs ◽

Sugarcane Cultivar ◽

Chromosome Transmission ◽

Long Time ◽

First Time

Within Erianthus , a genus close to Saccharum , the species E. arundinaceus has the potential to contribute valuable traits to sugarcane, including adaptation to biotic and abiotic stresses and ratooning ability. Sugarcane breeders have tried for a long time to use Erianthus species in their breeding programs but until recently were constrained by a lack of fertile Saccharum × Erianthus hybrids. We report here for the first time the chromosome composition of fertile Saccharum officinarum × E. arundinaceus F1, BC1 (F1 × sugarcane cultivar), and BC2 (BC1 × sugarcane cultivar) hybrids. The F1 and BC2 resulted from n + n chromosome transmission, while the BC1 resulted from 2n + n transmission. In the BC1 clones, the number of E. arundinaceus chromosomes ranged from 21 to 30, and in the BC2 clones, the number ranged from 14 to 15, revealing cases of chromosome loss. No recombination events between Saccharum and Erianthus chromosomes were observed in either the BC1 or BC2 clones. The implications of these results for introgression of genes from E. arundinaceus in sugarcane breeding programs are discussed. We propose a strategy to identify the agronomic value of chromosomes from E. arundinaceus and to conduct targeted breeding based on this information.

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Nonrandom Segregation of the Mouse Univalent X Chromosome: Evidence of Spindle-Mediated Meiotic Drive

Genetics ◽

10.1093/genetics/156.2.775 ◽

2000 ◽

Vol 156 (2) ◽

pp. 775-783 ◽

Cited By ~ 1

Author(s):

Renée LeMaire-Adkins ◽

Patricia A Hunt

Keyword(s):

X Chromosome ◽

Chromosome Abnormality ◽

Three Dimensional ◽

Fundamental Principle ◽

Mendelian Inheritance ◽

Segregation Behavior ◽

Chromosome Transmission ◽

Distortion Effect ◽

Random Segregation ◽

Transmission Distortion

Abstract A fundamental principle of Mendelian inheritance is random segregation of alleles to progeny; however, examples of distorted transmission either of specific alleles or of whole chromosomes have been described in a variety of species. In humans and mice, a distortion in chromosome transmission is often associated with a chromosome abnormality. One such example is the fertile XO female mouse. A transmission distortion effect that results in an excess of XX over XO daughters among the progeny of XO females has been recognized for nearly four decades. Utilizing contemporary methodology that combines immunofluorescence, FISH, and three-dimensional confocal microscopy, we have readdressed the meiotic segregation behavior of the single X chromosome in oocytes from XO females produced on two different inbred backgrounds. Our studies demonstrate that segregation of the univalent X chromosome at the first meiotic division is nonrandom, with preferential retention of the X chromosome in the oocyte in ∼60% of cells. We propose that this deviation from Mendelian expectations is facilitated by a spindle-mediated mechanism. This mechanism, which appears to be a general feature of the female meiotic process, has implications for the frequency of nondisjunction in our species.

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Multiple Heterologies Increase Mitotic Double-Strand Break-Induced Allelic Gene Conversion Tract Lengths in Yeast

Genetics ◽

10.1093/genetics/153.2.665 ◽

1999 ◽

Vol 153 (2) ◽

pp. 665-679 ◽

Cited By ~ 3

Author(s):

Jac A Nickoloff ◽

Douglas B Sweetser ◽

Jennifer A Clikeman ◽

Guru Jot Khalsa ◽

Sarah L Wheeler

Keyword(s):

Gene Conversion ◽

Mismatch Repair ◽

Frameshift Mutation ◽

Strand Break ◽

Double Strand Break ◽

Chromosome Loss ◽

Allelic Gene ◽

Break Induced Replication ◽

Gene Conversion Tract ◽

Conversion Tract

Abstract Spontaneous and double-strand break (DSB)-induced allelic recombination in yeast was investigated in crosses between ura3 heteroalleles inactivated by an HO site and a +1 frameshift mutation, with flanking markers defining a 3.4-kbp interval. In some crosses, nine additional phenotypically silent RFLP mutations were present at ∼100-bp intervals. Increasing heterology from 0.2 to 1% in this interval reduced spontaneous, but not DSB-induced, recombination. For DSB-induced events, 75% were continuous tract gene conversions without a crossover in this interval; discontinuous tracts and conversions associated with a crossover each comprised ∼7% of events, and 10% also converted markers in unbroken alleles. Loss of heterozygosity was seen for all markers centromere distal to the HO site in 50% of products; such loss could reflect gene conversion, break-induced replication, chromosome loss, or G2 crossovers. Using telomere-marked strains we determined that nearly all allelic DSB repair occurs by gene conversion. We further show that most allelic conversion results from mismatch repair of heteroduplex DNA. Interestingly, markers shared between the sparsely and densely marked interval converted at higher rates in the densely marked interval. Thus, the extra markers increased gene conversion tract lengths, which may reflect mismatch repair-induced recombination, or a shift from restoration- to conversion-type repair.

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The Role of Cdh1p in Maintaining Genomic Stability in Budding Yeast

Genetics ◽

10.1093/genetics/165.2.489 ◽

2003 ◽

Vol 165 (2) ◽

pp. 489-503 ◽

Cited By ~ 1

Author(s):

Karen E Ross ◽

Orna Cohen-Fix

Keyword(s):

Cell Cycle ◽

Chromosome Segregation ◽

Spindle Assembly Checkpoint ◽

Chromosome Loss ◽

Cyclin Dependent Kinase ◽

Anaphase Promoting Complex ◽

Growth Defects ◽

Genes Encoding ◽

Specificity Factor

Abstract Cdh1p, a substrate specificity factor for the cell cycle-regulated ubiquitin ligase, the anaphase-promoting complex/cyclosome (APC/C), promotes exit from mitosis by directing the degradation of a number of proteins, including the mitotic cyclins. Here we present evidence that Cdh1p activity at the M/G1 transition is important not only for mitotic exit but also for high-fidelity chromosome segregation in the subsequent cell cycle. CDH1 showed genetic interactions with MAD2 and PDS1, genes encoding components of the mitotic spindle assembly checkpoint that acts at metaphase to prevent premature chromosome segregation. Unlike cdh1Δ and mad2Δ single mutants, the mad2Δ cdh1Δ double mutant grew slowly and exhibited high rates of chromosome and plasmid loss. Simultaneous deletion of PDS1 and CDH1 caused extensive chromosome missegregation and cell death. Our data suggest that at least part of the chromosome loss can be attributed to kinetochore/spindle problems. Our data further suggest that Cdh1p and Sic1p, a Cdc28p/Clb inhibitor, have overlapping as well as nonoverlapping roles in ensuring proper chromosome segregation. The severe growth defects of both mad2Δ cdh1Δ and pds1Δ cdh1Δ strains were rescued by overexpressing Swe1p, a G2/M inhibitor of the cyclin-dependent kinase, Cdc28p/Clb. We propose that the failure to degrade cyclins at the end of mitosis leaves cdh1Δ mutant strains with abnormal Cdc28p/Clb activity that interferes with proper chromosome segregation.

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Mutational Analysis of the Drosophila Sister-Chromatid Cohesion Protein ORD and Its Role in the Maintenance of Centromeric Cohesion

Genetics ◽

10.1093/genetics/146.4.1319 ◽

1997 ◽

Vol 146 (4) ◽

pp. 1319-1331 ◽

Cited By ~ 1

Author(s):

Sharon E Bickel ◽

Dudley W Wyman ◽

Terry L Orr-Weaver

Keyword(s):

Sister Chromatid ◽

Mutational Analysis ◽

Germ Line ◽

Sister Chromatid Cohesion ◽

Chromosome Loss ◽

Male And Female ◽

Chromatid Cohesion ◽

Random Segregation ◽

Kinetochore Function ◽

Segregation Of Chromosomes

The ord gene is required for proper segregation of all chromosomes in both male and female Drosophila meiosis. Here we describe the isolation of a null ord allele and examine the consequences of ablating ord function. Cytologically, meiotic sister-chromatid cohesion is severely disrupted in flies lacking ORD protein. Moreover, the frequency of missegregation in genetic tests is consistent with random segregation of chromosomes through both meiotic divisions, suggesting that sister cohesion may be completely abolished. However, only a slight decrease in viability is observed for ord null flies, indicating that ORD function is not essential for cohesion during somatic mitosis. In addition, we do not observe perturbation of germ-line mitotic divisions in flies lacking ORD activity. Our analysis of weaker ord alleles suggests that ORD is required for proper centromeric cohesion after arm cohesion is released at the metaphase I/anaphase I transition. Finally, although meiotic cohesion is abolished in the ord null fly, chromosome loss is not appreciable. Therefore, ORD activity appears to promote centromeric cohesion during meiosis II but is not essential for kinetochore function during anaphase.

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Cytogenetic Findings in Primary Non-Small Cell Lung Cancer

Tumori Journal ◽

10.1177/030089169408000214 ◽

1994 ◽

Vol 80 (2) ◽

pp. 151-156

Author(s):

Elvira D'Alessandro ◽

Maria Luisa Lo Re ◽

Roberto Crisci ◽

Claudio Ligas ◽

Giorgio Furio Coloni

Keyword(s):

Lung Cancer ◽

Small Cell Lung Cancer ◽

Cell Lung Cancer ◽

Small Cell ◽

Chromosome Loss ◽

Small Cell Lung ◽

Primary Nsclc ◽

Cytogenetic Analyses ◽

Triploid Clone

Non-small cell lung cancer (NSCLC) shows a complex cytogenetic heterogeneity and up to now no particular chromosomal aberration seems to characterize its malignant evolution. We therefore performed cytogenetic analyses of 20 primary NSCLC, 8 adenocarcinomas and 12 squamous cell carcinomas on direct preparations or short-term cultures. Only 1 case was analyzed after long-term culture. Results were obtained from 11 samples and clonal rearrangements were found in 3 cases, a diploid and a near-triploid clone with several aberrations such as i (9q), rob (14; 15) and rob (21; 21) in 1 case, a near-triploid clone in 1 case, and Y chromosome loss in 1 case. Other aberrations found were sporadic, but + 7 aneuploidy and translocations involving 1p were detected in 2 and 3 samples respectively. Although to date it has been very difficult to recognize primary changes in NSCLC, nevertheless a literature review and our results indicate that i(9q) and robertsonian translocations are relevant findings.

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