scholarly journals Meiotic recombination-deficient mutants of Schizosaccharomyces pombe.

Genetics ◽  
1989 ◽  
Vol 123 (1) ◽  
pp. 45-54 ◽  
Author(s):  
A S Ponticelli ◽  
G R Smith
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Meiotic Recombination ◽  
Intragenic Recombination ◽  
Gene Products ◽  
Recombination Hotspot ◽  
Mutant Screen ◽  
Complementation Groups ◽  
Chromosome Iii ◽  
Rec Genes ◽  
Chromosome I

Abstract A mutant screen employing the ade6-M26 recombination hotspot was developed and used to isolate Schizosaccharomyces pombe mutants deficient in meiotic recombination. Nine rec mutations were recessive, defining six complementation groups, and reduced ade6 meiotic recombination 3-fold to greater than or equal to 300-fold when homozygous. Three recessive rec mutations analyzed further also reduced meiotic intragenic recombination at ura4 on chromosome III and intergenic recombination between pro2 and arg3 on chromosome I. The observed non-co-ordinate reductions of the recombinant frequencies in the three test intervals suggest a degree of locus (or intragenic vs. intergenic) specificity of the corresponding rec+ gene products. None of the mutations specifically inactivated the ade6-M26 hotspot. Additional rec genes may be identified with these methods.

scholarly journals Seventeen complementation groups of mutations decreasing meiotic recombination in Schizosaccharomyces pombe.

Genetics ◽  
1992 ◽  
Vol 130 (2) ◽  
pp. 251-262 ◽  
Author(s):  
L C De Veaux ◽  
N A Hoagland ◽  
G R Smith
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Meiotic Recombination ◽  
Class Ii ◽  
Class I ◽  
Intragenic Recombination ◽  
Class Iii ◽  
Multiple Alleles ◽  
Fold Reduction ◽  
Complementation Groups ◽  
Rec Genes

Abstract We have analyzed 43 recessive mutations reducing meiotic intragenic recombination in Schizosaccharomyces pombe. These mutations were isolated by a screen for reduced plasmid-by-chromosome recombination at the ade6 locus. Sixteen of the mutations define 10 new complementation groups, bringing to 17 the number of genes identified to be involved in meiotic recombination. The mutations were grouped into three discrete classes depending on the severity of the recombination deficiency in crosses involving the ade6-M26 recombination hotspot. Class I mutations caused at least a 1000-fold reduction in M26-stimulated intragenic recombination at the ade6 locus. Class II mutations reduced M26-stimulated recombination approximately 100-fold. Class III mutations caused a 3-10-fold reduction in either M26-stimulated or non-hotspot recombination. We obtained multiple alleles of class I and class II mutations, suggesting that we may be nearing saturation for mutations of this type. As a first step toward mapping, we used mitotic segregation to assign fourteen of the rec genes to chromosomes. Mutations in the six rec genes tested also caused a decrease in intragenic recombination at the ura4 locus; five of these mutations also reduced intergenic recombination between the pro2 and arg3 genes. These results indicate that these multiple rec gene products are required for high level meiotic recombination throughout the S. pombe genome.

scholarly journals Active and inactive transplacement of the M26 recombination hotspot in Schizosaccharomyces pombe.

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 33-48
Author(s):  
J B Virgin ◽  
J Metzger ◽  
G R Smith
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Meiotic Recombination ◽  
Plasmid Dna ◽  
Context Effect ◽  
Intragenic Recombination ◽  
Multicopy Plasmid ◽  
Chromosomal Locus ◽  
Sequence Element ◽  
Recombination Hotspot ◽  
Recombination Hotspots

Abstract The ade6-M26 mutation of the fission yeast Schizosaccharomyces pombe creates a meiotic recombination hotspot that elevates ade6 intragenic recombination approximately 10-15-fold. A heptanucleotide sequence including the M26 point mutation is required but not sufficient for hotspot activity. We studied the effects of plasmid and chromosomal context on M26 hotspot activity. The M26 hotspot was inactive on a multicopy plasmid containing M26 embedded within 3.0 or 5.9 kb of ade6 DNA. Random S. pombe genomic fragments totaling approximately 7 Mb did not activate the M26 hotspot on a plasmid. M26 hotspot activity was maintained when 3.0-, 4.4-, and 5.9-kb ade6-M26 DNA fragments, with various amounts of non-S. pombe plasmid DNA, were integrated at the ura4 chromosomal locus, but only in certain configurations relative to the ura4 gene and the cointegrated plasmid DNA. Several integrations created new M26-independent recombination hotspots. In all cases the non-ade6 DNA was located > 1 kb from the M26 site, and in some cases > 2 kb. Because the chromosomal context effect was transmitted over large distances, and did not appear to be mediated by a single discrete DNA sequence element, we infer that the local chromatin structure has a pronounced effect on M26 hotspot activity.

scholarly journals The Schizosaccharomyces pombe rec16 Gene Product Regulates Multiple Meiotic Events

Genetics ◽  
1997 ◽  
Vol 146 (1) ◽  
pp. 57-67
Author(s):  
Ywan Feng Li ◽  
Gerald R Smith
Keyword(s):  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Gene Product ◽  
Meiotic Recombination ◽  
Amino Acid Sequence Identity ◽  
Sequence Identity ◽  
Gene Functions ◽  
Complementation Groups ◽  
Rec Genes ◽  
Insight Into

Previously isolated meiotic recombination (rec) mutants of Schizosaccharomyces pombe define 16 complementation groups. The rec genes cloned and sequenced to date reveal little amino acid sequence identity to other reported proteins. We examined the rec mutants for alterations in meiotic events other than recombination to gain insight into the rec gene functions and to assess whether they affect recombination directly or indirectly. While mutations in the rec6–12, 14, 15 and 19 genes appeared to affect only meiotic recombination, a mutation in rec16 delayed meiotic DNA synthesis and, in some instances, reduced its amount; mitotic DNA synthesis was not detectably altered, indicating that the rec16 effect is limited to meiosis. In the rec16 mutant some meiotically induced transcripts (e.g., rec7 and 15) were significantly reduced in abundance, whereas others (e.g., rec10 and exo1) were induced and degraded with normal timing and extent during meiosis, indicating that the rec16 mutation leaves the basic meiotic program intact. These results indicate that the rec genes other than rec16 have their primary effect on meiotic recombination. In contrast, the rec16 gene product is essential for normal meiotic replication, recombination, and induction of some transcripts. These meiotic events may be coupled via a dependence of recombination and transcription on replication or via a cascade of gene expression.

scholarly journals Genetic and physical analysis of the M26 recombination hotspot of Schizosaccharomyces pombe.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 491-497
Author(s):  
A S Ponticelli ◽  
E P Sena ◽  
G R Smith
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Meiotic Recombination ◽  
Base Pair ◽  
Initiation Site ◽  
Mitotic Recombination ◽  
Physical Analysis ◽  
Nucleotide Change ◽  
Recombination Hotspot ◽  
Base Pair Mismatch

Abstract The ade6-M26 mutation of Schizosaccharomyces pombe has previously been reported to stimulate ade6 intragenic meiotic recombination. We report here that the ade6-M26 mutation is a single G----T nucleotide change, that M26 stimulated recombination within ade6 but not at other distinct loci, and that M26 stimulated meiotic but not mitotic recombination. In addition, M26 stimulated recombination within ade6 when M26 is homozygous; this result demonstrates that a base-pair mismatch at the M26 site was not required for the stimulation. These results are consistent with the ade6-M26 mutation creating a meiotic recombination initiation site.

Sequence requirement of the ade6-4095 meiotic recombination hotspot in Schizosaccharomyces pombe

Genetica ◽  
2017 ◽  
Vol 146 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Steven J. Foulis ◽  
Kyle R. Fowler ◽  
Walter W. Steiner
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Meiotic Recombination ◽  
Recombination Hotspot

scholarly journals Five RecA-like Proteins of Schizosaccharomyces pombe Are Involved in Meiotic Recombination

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1031-1043
Author(s):  
A L Grishchuk ◽  
J Kohli
Keyword(s):  
Escherichia Coli ◽  
Schizosaccharomyces Pombe ◽  
Meiotic Recombination ◽  
Sequence Similarity ◽  
Intragenic Recombination ◽  
Wild Type ◽  
Spore Viability ◽  
Viability Analysis ◽  
Recombination Protein ◽  
Recombination Gene

Abstract The genome of Schizosaccharomyces pombe contains five genes that code for proteins with sequence similarity to the Escherichia coli recombination protein RecA: rad51+, rhp55+, rhp57+, rlp1+, and dmc1+. We analyzed the effect of deletion of each of these genes on meiotic recombination and viability of spores. Meiotic recombination levels were different from wild type in all recA-related mutants in several genetic intervals, suggesting that all five RecA homologs of S. pombe are required for normal levels of meiotic recombination. Spore viability was reduced in rad51, rhp55, and rhp57 mutants, but not in rlp1 and dmc1. It is argued that reduction of crossover is not the only cause for the observed reduction of spore viability. Analysis of double and triple mutants revealed that Rad51 and Dmc1 play major and partially overlapping roles in meiotic recombination, while Rhp55, Rhp57, and Rlp1 play accessory roles. Remarkably, deletion of Rlp1 decreases the frequency of intergenic recombination (crossovers), but increases intragenic recombination (gene conversion). On the basis of our results, we present a model for the involvement of five RecA-like proteins of S. pombe in meiotic recombination and discuss their respective roles.

scholarly journals Identification of new genes required for meiotic recombination in Saccharomyces cerevisiae.

Genetics ◽  
1993 ◽  
Vol 133 (1) ◽  
pp. 51-66 ◽  
Author(s):  
M Ajimura ◽  
S H Leem ◽  
H Ogawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Specific Gene ◽  
Early Step ◽  
Haploid Strain ◽  
New Genes ◽  
Intragenic Complementation ◽  
Complementation Groups ◽  
Chromosome Iii ◽  
Unusual Phenotype

Abstract Mutants defective in meiotic recombination were isolated from a disomic haploid strain of Saccharomyces cerevisiae by examining recombination within the leu2 and his4 heteroalleles located on chromosome III. The mutants were classified into two new complementation groups (MRE2 and MRE11) and eight previously identified groups, which include SPO11, HOP1, REC114, MRE4/MEK1 and genes in the RAD52 epistasis group. All of the mutants, in which the mutations in the new complementation groups are homozygous and diploid, can undergo premeiotic DNA synthesis and produce spores. The spores are, however, not viable. The mre2 and mre11 mutants produce viable spores in a spo13 background, in which meiosis I is bypassed, suggesting that these mutants are blocked at an early step in meiotic recombination. The mre2 mutant does not exhibit any unusual phenotype during mitosis and it is, thus, considered to have a mutation in a meiosis-specific gene. By contrast, the mre11 mutant is sensitive to damage to DNA by methyl methanesulfonate and exhibits a hyperrecombination phenotype in mitosis. Among six alleles of HOP1 that were isolated, an unusual pattern of intragenic complementation was observed.

scholarly journals Genetical analysis of proline mutants and their suppressors in Aspergillus nidulans

1966 ◽  
Vol 8 (3) ◽  
pp. 311-321 ◽  
Author(s):  
P. Weglenski
Keyword(s):  
Aspergillus Nidulans ◽  
Reversion Rate ◽  
Genetical Analysis ◽  
The Third ◽  
Suppressor Mutations ◽  
Spontaneous Reversion ◽  
Complementation Groups ◽  
Chromosome Iii ◽  
Chromosome I ◽  
Increased Activity

1.Complementation between thirteen proline auxotrophs in A. nidulans was studied. Two groups of mutants with different complementation pattern were found. These two groups could also be distinguished on the basis of recombination tests.2. The spontaneous reversion rate of proline mutants was established. In all cases studied the reversions were due to suppressor mutations. Dominant, semi-dominant and recessive suppressors were distinguished.3. Complementation between recessive suppressors was studied. Only a few of the suppressors obtained could be located in different complementation groups.4. Three suppressor loci were mapped, two of them, su-2 and su-6 in chromosome III linked to the phen-2 locus, respectively 22 and 26 map units distant, and the third in chromosome I, linked to the ad-9 locus (1·9 map units). su-2 is a mutant at the Su-4 pro locus already identified by Forbes (1956).5. The action of these suppressors is thought to consist in affecting the pathway of arginine synthesis by one of three mechanisms: (1) accumulation of an inter mediate (ornithine); (2) increased activity of ornithine δ-transaminase; and (3) a third, as yet, unclear process possibly involving feed-back regulation of arginine synthesis or the regulation of arginine breakdown to ornithine.

scholarly journals A Family of cAMP-Response-Element-Related DNA Sequences With Meiotic Recombination Hotspot Activity in Schizosaccharomyces pombe

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 59-68
Author(s):  
Mary E Fox ◽  
Takatomi Yamada ◽  
Kunihiro Ohta ◽  
Gerald R Smith
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Dna Sequences ◽  
Meiotic Recombination ◽  
Consensus Sequence ◽  
Micrococcal Nuclease ◽  
Open Chromatin ◽  
Camp Response Element ◽  
Response Element ◽  
Recombination Hotspot ◽  
Single Sequence

Abstract The heptamer sequence ATGACGT is essential for activity of the M26 meiotic recombination hotspot in the ade6 gene of Schizosaccharomyces pombe. Hotspot activity is associated with binding of the heterodimeric transcription factor Atf1·Pcr1 to M26. We have found that the sequences (C/T/G) TGACGT also bound Atf1·Pcr1 and acted as meiotic hotspots, but unlike M26 they must be followed by A or C for Atf1·Pcr1 binding and hotspot activity. The basis of the hotspot activity of CTGACGTA (ade6-3013) appears to be identical to that of M26: hotspot activity of both sequences was abolished in cells mutant for atf1, pcr1, spc1, or wis1 and was undetectable in mitotic recombination and in meiotic recombination when located on a plasmid. Both hotspot sequences were sites of micrococcal nuclease hypersensitivity in meiotic chromatin, suggesting that they create an open chromatin structure during meiosis at the site of the hotspots. The newly identified hotspot sequences (C/T/G)TGACGT(A/C) and M26 are closely related to the cAMP response element (CRE) consensus sequence for binding of cAMP-responsive transcription factors such as Atf1·Pcr1, suggesting a link between transcription and meiotic recombination. These results significantly expand the list of identified sequences with meiotic recombination hotspot activity in S. pombe from a single sequence to a family of CRE-related sequences.

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