scholarly journals Common Regulation of Recombination at the Amination-1 and Histidine-2 Loci In Neurospora Crassa

1971 ◽  
Vol 24 (1) ◽  
pp. 107 ◽  
Author(s):  
DG Catcheside ◽  
Barnbara Austin
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Group I

Recombination between alleles is reduced by rec-3+ at the am-J locus and by rec-x+ at the his-2 locus. The two recombination genes are both in the same region of the left arm of linkage group I between acr-3 and arg-3. All known stocks are either rec-3 rec-x or rec-3+ ree-x+. Recombination between ree-3 arid ree-x is less than 0�143%, with 95% probability. The evidence suggests that the two ree genes are the same, although they act on unrelated loci.

Cloning, sequence, and photoregulation of al-1, a carotenoid biosynthetic gene of Neurospora crassa

1990 ◽  
Vol 10 (10) ◽  
pp. 5064-5070
Author(s):  
T J Schmidhauser ◽  
F R Lauter ◽  
V E Russo ◽  
C Yanofsky
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Carotenoid Biosynthesis ◽  
Mrna Levels ◽  
Biosynthetic Gene ◽  
Biosynthetic Enzyme ◽  
Group I ◽  
Phytoene Dehydrogenase ◽  
Initiation Of Transcription ◽  
Residue Polypeptide

Carotenoid biosynthesis is regulated by blue light during growth of Neurospora crassa mycelia. We have cloned the al-1 gene of N. crassa encoding the carotenoid-biosynthetic enzyme phytoene dehydrogenase and present an analysis of its structure and regulation. The gene encodes a 595-residue polypeptide that shows homology to two procaryotic carotenoid dehydrogenases. RNA measurements showed that the level of al-1 mRNA increased over 70-fold in photoinduced mycelia. Transcription run-on studies indicated that the al-1 gene was regulated at the level of initiation of transcription in response to photoinduction. The photoinduced increase of al-1 mRNA levels was not observed in two Neurospora mutants defective in all physiological photoresponses. Analysis of cosmid containing al-1 and of a translocation strain with a breakpoint within al-1 indicated that al-1 transcription proceeds towards the centromere of linkage group I of N. crassa.

GENETIC AND COMPLEMENTATION STUDIES OF A NEW CAROTENOID MUTANT OF NEUROSPORA CRASSA

1968 ◽  
Vol 10 (2) ◽  
pp. 351-356 ◽  
Author(s):  
R. E. Subden ◽  
S. F. H. Threlkeld
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Biosynthetic Pathway ◽  
Group I ◽  
The Right

A spontaneously occurring mutant called "yellow b" has been isolated and mapped on the right arm of linkage group I in Neurospora crassa 0.15 c.o.u. distal to aur and 2 c.o.u. distal to al-2. These three markers complement each other and are involved in the same biosynthetic pathway.

NULL MUTANTS OF THE A AND a MATING TYPE ALLELES OF NEUROSPORA CRASSA

1982 ◽  
Vol 24 (2) ◽  
pp. 167-176 ◽  
Author(s):  
A. J. F. Griffiths
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Uv Irradiation ◽  
Mating Type ◽  
Opposite Mating Type ◽  
Extended Study ◽  
Fundamental Properties ◽  
Group I ◽  
Sexual Compatibility ◽  
Null Mutants

Thirty-five null mutants have now been obtained of the A mating type allele, which have simultaneously lost both known functions-heterokaryon incompatibility and sexual compatibility with strains of the opposite mating type, a. The mutants, designated Am, were obtained by selecting for heterokaryon compatibility following UV-irradiation of the normal A. Twenty-five of the mutations were viable as homokaryons. Both functions reverted together when two of these were irradiated. In most respects, Am mutations resemble the previously reported am mutations in their behavior. The Am mutations differ, however, in failing to produce illegitimate empty perithecia in crosses with testers of the same mating type from which they originated. — The previously obtained am mutants were characterized further. It was confirmed that these am mutants show abortive mating reactions, legitimate and illegitimate, with several tester strains, thus showing that such reactions are fundamental properties of the mutants themselves. In support of this, it was shown that the A-like behavior of am strains in the illegitimate reaction is not due to acquisition of determining elements through cytoplasmic contact with A in heterokaryons. It is possible that the sterile am mutants can be carried through a cross by a fertile heterokaryotic partner, but an extended study of meiotic products presumed to stem from this process confirmed that if such a process occurs it can involve no recombination on linkage group I. The single fertile am mutant was shown to have normal recombination on L.G.I. Escape from (A + a) incompatibility was shown to be possible in the identical heterokaryon used for am induction. Escape cannot be ruled out as a source of nonrecoverable am mutations.

scholarly journals Interspecific crosses and crossing-over in Neurospora

1972 ◽  
Vol 19 (2) ◽  
pp. 115-119 ◽  
Author(s):  
K. D. Newcombe ◽  
S. F. H. Threlkeld
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Interspecific Crosses ◽  
Crossing Over ◽  
Centromere Region ◽  
Group I

SUMMARYThrough a series of backcrosses the centromere region of linkage group I of Neurospora crassa was transferred to the N. sitophila genome, and through another series of backcrosses the centromere region of linkage group I of N. sitophila was transferred to N. crassa. Strains thus synthesized showed, in further crosses, that the N. sitophila centromere region acts as a dominant enhancer of cross-over frequencies across linkage group I of the two species.

AN INTERSTITIAL PERICENTRIC INVERSION IN NEUROSPORA

1982 ◽  
Vol 24 (6) ◽  
pp. 693-703 ◽  
Author(s):  
Edward G. Barry ◽  
John F. Leslie
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Gene Order ◽  
Pericentric Inversion ◽  
Inverted Segment ◽  
Chromosome Inversions ◽  
Central Segment ◽  
Group I ◽  
Higher Eukaryotes ◽  
Inversion Loop

In ln(IL; IR)OY323 of Neurospora crassa, a long central segment of linkage group I is inverted that includes the centromere. This is the first interstitial pericentric inversion to be identified in a fungus. In genetic and cytological behavior, it resembles chromosome inversions in higher eukaryotes. In crosses heterozygous for the OY323 inversion, normally distant markers are closely linked, while in homozygous inversion crosses the gene order is reversed, but recombination is approximately normal within the inverted segment. A characteristic inversion loop may form at pachytene in heterozygous crosses; frequently, segments distal to the breakpoints do not pair, however. Rearrangement breakpoints were mapped precisely by duplication coverage using appropriate recessive markers in crosses of OY323 with a partially overlapping inversion, In(IL→IR)NM176.

scholarly journals Physical mapping of meiotic crossover events in a 200-kb region of Neurospora crassa linkage group I.

Genetics ◽  
1993 ◽  
Vol 134 (4) ◽  
pp. 1077-1083
Author(s):  
M R Mautino ◽  
S D Haedo ◽  
A L Rosa
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Fragment Length Polymorphism ◽  
Physical Distance ◽  
Linkage Maps ◽  
Chromosome Walking ◽  
Group I ◽  
Meiotic Crossover ◽  
Genetic Interval ◽  
General Restriction

Abstract We propose a general restriction fragment length polymorphism-based strategy to analyze the distribution of meiotic crossover events throughout specific genetic intervals. We have isolated 64 recombinant chromosomes carrying independent meiotic crossover events in the genetic interval eth-1-un-2 on linkage group I of Neurospora crassa. Thirty-eight crossover events were physically mapped with reference to a 200-kb region cloned by chromosome walking, using N. crassa lambda and cosmid libraries. Crossovers were homogeneously distributed at intervals of 5.0 +/- 2.3 kb along the entire cloned interval. The ratio of physical to genetic distance appears to be higher in the region than in the overall N. crassa genome, suggesting that recombinational activity is less in large chromosomes than in small ones. The present work provides a method for defining the centromeric-telomeric orientation of single cloned DNA fragments. Their physical distance can also be estimated with respect to linked loci, provided that crossover events are distributed homogeneously in the interval. This strategy overcomes typical difficulties in defining the position and direction of chromosome walking steps on conventional linkage maps.

scholarly journals Genetic recombination in Neurospora crassa and N. sitophila

1965 ◽  
Vol 6 (2) ◽  
pp. 216-225 ◽  
Author(s):  
M. B. Scott-Emuakpor
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Mating Type ◽  
Genetic Recombination ◽  
Evolutionary Significance ◽  
Linkage Groups ◽  
Group Vi ◽  
Group I ◽  
Mutant Genes ◽  
Type Chromosome

Mutant genes in linkage groups I (mating-type chromosome), VI and VII have been transferred from Neurospora crassa to N. sitophila by hybridization and repeated backcrossing. Recombination between these genes has been studied from five-point crosses involving linkage group I and three-point crosses involving linkage groups VI and VII of the two species.The results show significant differences in the amount of recombination between some of the genes in the proximal regions of the mating-type chromosomes of the two species. They indicate proximal localization of crossovers in the mating-type chromosome of N. sitophila. The results also show significant differences in recombination frequency between the genes in linkage group VI and a close similarity in linkage group VII. They further show that the centromere in the two species may not be interfering with crossing-over in its vicinity to such an extent as to be of any evolutionary significance.

scholarly journals Characterization of the new osmotic mutants (os) which originated during genetic transformation inNeurospora crassa

1977 ◽  
Vol 29 (1) ◽  
pp. 9-19 ◽  
Author(s):  
N. C. Mishra
Keyword(s):  
Linkage Group ◽  
Genetic Transformation ◽  
Neurospora Crassa ◽  
Wild Type ◽  
Induced Mutation ◽  
Group I ◽  
Intragenic Complementation ◽  
Inneurospora Crassa ◽  
New Alleles

SUMMARYInositol independent (inl+) strains were obtained either as transformants following treatment of the inositol requiring (inl) strains ofNeurospora crassawith the wild-type DNA or as revertants without any DNA treatment. A significant number of the inositol-independent transformants were also found to have acquired additional mutations called osmotics (os) which made them unable to grow on 1 m-NaCl medium. None of the inositol-independent revertants were found to possess such osmotic mutations and their growth remained unaffected by the presence of NaCl. Many of the osmotic mutants described here were found to be new alleles of the previously knownos–1mutation on the linkage group I ofNeurospora crassa. The remainder were found to map at two new genetic loci designated asos-6andos-7; these loci were found to be closely linked toos–1. Among the new osmotic mutants onlyos-1andos-6mutants showed intragenic complementation. The mechanism of DNA-induced mutation during transformation is discussed.

scholarly journals Cloning, sequence, and photoregulation of al-1, a carotenoid biosynthetic gene of Neurospora crassa.

1990 ◽  
Vol 10 (10) ◽  
pp. 5064-5070 ◽  
Author(s):  
T J Schmidhauser ◽  
F R Lauter ◽  
V E Russo ◽  
C Yanofsky
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Carotenoid Biosynthesis ◽  
Mrna Levels ◽  
Biosynthetic Gene ◽  
Biosynthetic Enzyme ◽  
Group I ◽  
Phytoene Dehydrogenase ◽  
Initiation Of Transcription ◽  
Residue Polypeptide

Carotenoid biosynthesis is regulated by blue light during growth of Neurospora crassa mycelia. We have cloned the al-1 gene of N. crassa encoding the carotenoid-biosynthetic enzyme phytoene dehydrogenase and present an analysis of its structure and regulation. The gene encodes a 595-residue polypeptide that shows homology to two procaryotic carotenoid dehydrogenases. RNA measurements showed that the level of al-1 mRNA increased over 70-fold in photoinduced mycelia. Transcription run-on studies indicated that the al-1 gene was regulated at the level of initiation of transcription in response to photoinduction. The photoinduced increase of al-1 mRNA levels was not observed in two Neurospora mutants defective in all physiological photoresponses. Analysis of cosmid containing al-1 and of a translocation strain with a breakpoint within al-1 indicated that al-1 transcription proceeds towards the centromere of linkage group I of N. crassa.

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