scholarly journals The Ade6-M26 Mutation of Schizosaccharomyces Pombe Increases the Frequency of Crossing over.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 507-515
Author(s):  
P Schuchert ◽  
J Kohli
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Marker Gene ◽  
Crossing Over ◽  
Crossover Frequency ◽  
Tetrad Analysis ◽  
Ectopic Recombination ◽  
Homologous Sequences ◽  
New Information ◽  
Conversion Frequency

Abstract The ade6-M26 mutation of Schizosaccharomyces pombe increases conversion frequency in comparison with the nearby mutation ade6-M375. In order to investigate the effect of ade6-M26 on crossover frequency, heteroallelic ade6 duplications were constructed by integration of plasmids carrying the marker gene ura4. One ade6 gene carries either of the mutations M26 or M375 while the other ade6 copy carries the L469 mutation in both duplications. The duplication with ade6-M26 yields Ade(+) recombinants at significantly higher frequencies in meiosis, but not in mitosis. Tetrad analysis and physical characterization of spore clones from recombination tetrads demonstrate that conversions, unequal crossovers and intrachromatid exchanges occur at higher frequencies but with unaltered proportions among them. The conversion events show a pronounced bias when M26 is involved: they take place preferentially at the M26 allele. Thus the ade6-M26 mutation not only enhances conversion frequency as demonstrated before, but also crossover frequency. It displays the properties expected for a preferred site of initiation of general meiotic recombination. The duplications also yielded new information on ectopic recombination in S. pombe: ectopic crossovers occur in the duplications at much higher frequency than among naturally dispersed homologous sequences.

scholarly journals The M26 Hotspot of Schizosaccharomyces pombe Stimulates Meiotic Ectopic Recombination and Chromosomal Rearrangements

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1191-1204 ◽  
Author(s):  
Jeffrey B Virgin ◽  
Jeffrey P Bailey
Keyword(s):  
Homologous Recombination ◽  
Schizosaccharomyces Pombe ◽  
Dna Sequences ◽  
Chromosomal Rearrangements ◽  
Low Frequency ◽  
Repeated Sequences ◽  
Crossing Over ◽  
Ectopic Recombination ◽  
Recombination Hotspots ◽  
Integration Sites

Abstract Homologous recombination is increased during meiosis between DNA sequences at the same chromosomal position (allelic recombination) and at different chromosomal positions (ectopic recombination). Recombination hotspots are important elements in controlling meiotic allelic recombination. We have used artificially dispersed copies of the ade6 gene in Schizosaccharomyces pombe to study hotspot activity in meiotic ectopic recombination. Ectopic recombination was reduced 10–1000-fold relative to allelic recombination, and was similar to the low frequency of ectopic recombination between naturally repeated sequences in S. pombe. The M26 hotspot was active in ectopic recombination in some, but not all, integration sites, with the same pattern of activity and inactivity in ectopic and allelic recombination. Crossing over in ectopic recombination, resulting in chromosomal rearrangements, was associated with 35–60% of recombination events and was stimulated 12-fold by M26. These results suggest overlap in the mechanisms of ectopic and allelic recombination and indicate that hotspots can stimulate chromosomal rearrangements.

scholarly journals Isolation and characterization of Schizosaccharomyces pombe mutants affected in mitotic recombination.

Genetics ◽  
1991 ◽  
Vol 128 (3) ◽  
pp. 495-504
Author(s):  
A Gysler-Junker ◽  
Z Bodi ◽  
J Kohli
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Mitotic Recombination ◽  
Selective Medium ◽  
Intragenic Recombination ◽  
Crossing Over ◽  
Wild Type ◽  
Isolation And Characterization ◽  
Mitotic Gene Conversion ◽  
Type Frequency

Abstract A haploid Schizosaccharomyces pombe strain carrying a heteroallelic duplication of the ade6 gene was used to isolate mitotic recombination-deficient mutants. Recombination between the different copies of the ade6 gene can lead to Ade+ segregants. These are observed as growing papillae when colonies of a suitable size are replicated onto selective medium. We isolated mutants which show an altered papillation phenotype. With two exceptions, they exhibit a decrease in the frequency of mitotic recombination between the heteroalleles of the duplication. The two other mutants display a hyper-recombination phenotype. The 12 mutations were allocated to at least nine distinct loci by recombination tests. Of the eight rec mutants analyzed further, six were also affected in mitotic intergenic recombination in the intervals cen2-mat or cen3-arg 1. No effect on mitotic intragenic recombination was observed. These data suggest that mitotic gene conversion and crossing over can be separated mutationally. Meiotic recombination occurs at the wild-type frequency in all mutants investigated.

scholarly journals Crossing Over Is Rarely Associated With Mitotic Intragenic Recombination in Schizosaccharomyces pombe

Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Jeffrey B Virgin ◽  
Jeffrey P Bailey ◽  
Farnaz Hasteh ◽  
James Neville ◽  
Amy Cole ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Chromosomal Rearrangements ◽  
Mitotic Recombination ◽  
Intragenic Recombination ◽  
Crossing Over ◽  
Recombination Rates ◽  
Alternative Pathways ◽  
Ectopic Recombination ◽  
Specific Factors ◽  
Differential Control

Abstract Chromosomal rearrangements can result from crossing over during ectopic homologous recombination between dispersed repetitive DNA. We have previously shown that meiotic ectopic recombination between artificially dispersed ade6 heteroalleles in the fission yeast Schizosaccharomyces pombe frequently results in chromosomal rearrangements. The same recombination substrates have been studied in mitotic recombination. Ectopic recombination rates in haploids were ∼1-4 × 10-6 recombinants per cell generation, similar to allelic recombination rates in diploids. In contrast, ectopic recombination rates in heterozygous diploids were 2.5-70 times lower than allelic recombination or ectopic recombination in haploids. These results suggest that diploid-specific factors inhibit ectopic recombination. Very few crossovers occurred in ade6 mitotic recombination, either allelic or ectopic. Allelic intragenic recombination was associated with 2% crossing over, and ectopic recombination between multiple different pairing partners showed 1-7% crossing over. These results contrast sharply with the 35-65% crossovers associated with meiotic ade6 recombination and suggest either differential control of resolution of recombination intermediates or alternative pathways of recombination in mitosis and meiosis.

scholarly journals Genetic and Molecular Characterization of the Maizerp3Rust Resistance Locus

Genetics ◽  
2002 ◽  
Vol 162 (1) ◽  
pp. 381-394 ◽  
Author(s):  
Craig A Webb ◽  
Todd E Richter ◽  
Nicholas C Collins ◽  
Marie Nicolas ◽  
Harold N Trick ◽  
...  
Keyword(s):  
Family Members ◽  
Crossing Over ◽  
Resistance Locus ◽  
Leucine Rich Repeat ◽  
Bac Contig ◽  
Puccinia Sorghi ◽  
Coding Regions ◽  
Complex Locus ◽  
Sequence Identities

AbstractIn maize, the Rp3 gene confers resistance to common rust caused by Puccinia sorghi. Flanking marker analysis of rust-susceptible rp3 variants suggested that most of them arose via unequal crossing over, indicating that rp3 is a complex locus like rp1. The PIC13 probe identifies a nucleotide binding site-leucine-rich repeat (NBS-LRR) gene family that maps to the complex. Rp3 variants show losses of PIC13 family members relative to the resistant parents when probed with PIC13, indicating that the Rp3 gene is a member of this family. Gel blots and sequence analysis suggest that at least 9 family members are at the locus in most Rp3-carrying lines and that at least 5 of these are transcribed in the Rp3-A haplotype. The coding regions of 14 family members, isolated from three different Rp3-carrying haplotypes, had DNA sequence identities from 93 to 99%. Partial sequencing of clones of a BAC contig spanning the rp3 locus in the maize inbred line B73 identified five different PIC13 paralogues in a region of ∼140 kb.

scholarly journals Characterization of Glycoside Hydrolase Family 5 Proteins in Schizosaccharomyces pombe

2010 ◽  
Vol 9 (11) ◽  
pp. 1650-1660 ◽  
Author(s):  
Encarnación Dueñas-Santero ◽  
Ana Belén Martín-Cuadrado ◽  
Thierry Fontaine ◽  
Jean-Paul Latgé ◽  
Francisco del Rey ◽  
...  
Keyword(s):  
Cell Wall ◽  
Schizosaccharomyces Pombe ◽  
Protein Characterization ◽  
Wall Material ◽  
Glycoside Hydrolase Family ◽  
Content Type ◽  
Hydrolysis Of ◽  
Controlled Hydrolysis ◽  
Hydrolase Family

ABSTRACT In yeast, enzymes with β-glucanase activity are thought to be necessary in morphogenetic events that require controlled hydrolysis of the cell wall. Comparison of the sequence of the Saccharomyces cerevisiae exo-β(1,3)-glucanase Exg1 with the Schizosaccharomyces pombe genome allowed the identification of three genes that were named exg1 + (locus SPBC1105.05), exg2 + (SPAC12B10.11), and exg3 + (SPBC2D10.05). The three proteins have different localizations: Exg1 is secreted to the periplasmic space, Exg2 is a membrane protein, and Exg3 is a cytoplasmic protein. Characterization of the biochemical activity of the proteins indicated that Exg1 and Exg3 are active only against β(1,6)-glucans while no activity was detected for Exg2. Interestingly, Exg1 cleaves the glucans with an endohydrolytic mode of action. exg1 + showed periodic expression during the cell cycle, with a maximum coinciding with the septation process, and its expression was dependent on the transcription factor Sep1. The Exg1 protein localizes to the septum region in a pattern that was different from that of the endo-β(1,3)-glucanase Eng1. Overexpression of Exg2 resulted in an increase in cell wall material at the poles and in the septum, but the putative catalytic activity of the protein was not required for this effect.

Identification and Characterization of the rhp23+ DNA Repair Gene in Schizosaccharomyces pombe

2000 ◽  
Vol 268 (1) ◽  
pp. 210-215 ◽  
Author(s):  
Marcel Lombaerts ◽  
Jerrelyne I. Goeloe ◽  
Hans den Dulk ◽  
Jourica A. Brandsma ◽  
Jaap Brouwer
Keyword(s):  
Dna Repair ◽  
Schizosaccharomyces Pombe ◽  
Repair Gene ◽  
Dna Repair Gene ◽  
Identification And Characterization

scholarly journals Static Atomic Displacements in Crystalline Solid Solution Alloys

1996 ◽  
Vol 437 ◽  
Author(s):  
Gene Ice ◽  
Cullie Sparks ◽  
J. Lee Robertson ◽  
J. Ernest Epperson ◽  
Xiaogang Jiang
Keyword(s):  
Synchrotron Radiation ◽  
Crystalline Solid ◽  
Local Order ◽  
Chemical Order ◽  
X Ray ◽  
Atomic Displacements ◽  
X Ray Scattering ◽  
New Information ◽  
Z Contrast

AbstractAtom size differences induce static displacements from an average alloy lattice and play an important role in controlling alloy phase stability and properties. The details of this role however, are difficult to study; chemical order and displacements are strongly interrelated and static displacements are hard to measure. Diffuse x-ray scattering measurements with tunable-synchrotron radiation can now measure element-specific static displacements with an accuracy of ± 0.1 pm and can simultaneously measure local chemical order out to 20 shells or more. Ideal alloys for diffuse scattering analysis with synchrotron radiation, are those that have previously been the most intractable: alloys with small Z contrast, alloys with only local order and alloys with small size differences. The combination of precise characterization of local chemical order and precise measurement of static displacement provides new information that challenges existing alloy models. We report on an ongoing systematic study of static displacements in the Fe/Ni/Cr alloys and compare the observed static displacements to the static displacements predicted by current theories. The availability of more brilliant 3rd generation hard x-ray sources will greatly enhance these measurements.

Partial characterization of an RNA component that copurifies with Saccharomyces cerevisiae RNase P

1989 ◽  
Vol 9 (6) ◽  
pp. 2536-2543
Author(s):  
J Y Lee ◽  
D R Engelke
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Secondary Structure ◽  
Schizosaccharomyces Pombe ◽  
Rnase P ◽  
Partial Characterization ◽  
Rna Sequences ◽  
Extensive Sequence ◽  
Sequence Similarities

Saccharomyces cerevisiae cellular RNase P is composed of both protein and RNA components that are essential for activity. The isolated holoenzyme contains a highly structured RNA of 369 nucleotides that has extensive sequence similarities to the 286-nucleotide RNA associated with Schizosaccharomyces pombe RNase P but bears little resemblance to the analogous RNA sequences in procaryotes or S. cerevisiae mitochondria. Even so, the predicted secondary structure of S. cerevisiae RNA is strikingly similar to the bacterial phylogenetic consensus rather than to previously predicted structures of other eucaryotic RNase P RNAs.

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