“No-growth”-Complementation in Forced Heterokaryons from Sorbose-Resistant (Transport-Defective) Neurospora crassa Mutants

1967 ◽  
Vol 22 (10) ◽  
pp. 1024-1027 ◽  
Author(s):  
Walter Klingmüller ◽  
Fritz Kaudewitz
Keyword(s):  
Neurospora Crassa ◽  
Type A ◽  
Double Heterozygote ◽  
Linkage Groups ◽  
Wildtype Strain ◽  
Pairwise Combination ◽  
Functional Relations ◽  
Intermediate Expression

Studies on heterokaryons forced between sorbose-resistant (transport-defective) mutans of Neurospora crassa and a sorbose-sensitive (transport-intact) wildtype strain show that mutants sorr A-1 and sorr B-57, mapping in separate linkage groups, are recessive to wildtype; a third mutant, not linked to the others, shows intermediate expression of the resistance character for one of two criteria considered.The functional relations between sorr-loci A and B and the amount of resistance caused by defects in both of them have been investigated in forced heterokaryons of the type A-B + A-B, AB-+AB- and A-B + AB-. Pairwise combination of A- with B- resulted in complementation to the sorbose-sensitive wild-phenotype (“no-growth” complementation). The occurrence of no-growth complementation in the double heterozygote supports the conclusion derived earlier that both gene loci A and B are coding for permeases responsible for the uptake of sorbose.

scholarly journals An electrophoretic karyotype of Neurospora crassa.

1988 ◽  
Vol 8 (4) ◽  
pp. 1469-1473 ◽  
Author(s):  
M J Orbach ◽  
D Vollrath ◽  
R W Davis ◽  
C Yanofsky
Keyword(s):  
Neurospora Crassa ◽  
Electric Fields ◽  
Gel Electrophoresis ◽  
Electrophoretic Karyotype ◽  
Dna Molecules ◽  
Linkage Groups ◽  
Homogeneous Electric Field ◽  
Chromosomal Dna ◽  
Molecular Karyotype ◽  
Electrophoresis System

A molecular karyotype of Neurospora crassa was obtained by using an alternating-field gel electrophoresis system which employs contour-clamped homogeneous electric fields. The migration of all seven N. crassa chromosomal DNAs was defined, and five of the seven molecules were separated from one another. The estimated sizes of these molecules, based on their migration relative to Schizosaccharomyces pombe chromosomal DNA molecules, are 4 to 12.6 megabases. The seven linkage groups were correlated with specific chromosomal DNA bands by hybridizing transfers of contour-clamped homogeneous electric field gels with radioactive probes specific to each linkage group. The mobilities of minichromosomal DNAs generated from translocation strains were also examined. The methods used for preparation of chromosomal DNA molecules and the conditions for their separation should be applicable to other filamentous fungi.

scholarly journals Heterogeneity in recombination frequencies in Neurospora crassa

1961 ◽  
Vol 2 (1) ◽  
pp. 43-62 ◽  
Author(s):  
L. C. Frost
Keyword(s):  
Neurospora Crassa ◽  
Wild Type ◽  
Linkage Groups ◽  
Genetic Determination ◽  
Wild Strains ◽  
Genetically Determined ◽  
Homogeneous Data

The available data on heterogeneity in centromere distances for a number of loci in several linkage groups are analysed and interpreted. When the crosses are grouped according to wild-type ancestry, heterogeneity is eliminated in any one group except those which consist of backcrosses or intercrosses. Abbott 4 and 12 are shown to be the source of the heterogeneity while Lindegren and probably Chilton wild strains give consistent, homogeneous distances. In a cross between Abbott 12 and Lindegren wild-types, the centromere distances of mt and asco show heterogeneous values between the spore pairs in an ascus indicating that significantly different distances are genetically determined and that the factors concerned show segregation. The genetic determination differs in the various wild strains; the data suggest that at least three factors are involved. In random spore analyses heterogeneity is present in recombination frequencies between linked markers either proximal or distal to their centromere. The mechanism by which heterogeneity in the data might arise is discussed. To obtain homogeneous data it is suggested that all markers used should be repeatedly backcrossed to the Lindegren wild-type.

scholarly journals REGULATION OF PHOSPHATE METABOLISM IN NEUROSPORA CRASSA: IDENTIFICATION OF THE STRUCTURAL GENE FOR REPRESSIBLE ACID PHOSPHATASE

Genetics ◽  
1976 ◽  
Vol 84 (2) ◽  
pp. 183-192
Author(s):  
Robert E Nelson ◽  
John F Lehman ◽  
Robert L Metzenberg
Keyword(s):  
Acid Phosphatase ◽  
Neurospora Crassa ◽  
Structural Gene ◽  
Group Iv ◽  
Structural Genes ◽  
Wild Type ◽  
Linkage Groups ◽  
Michaelis Constant ◽  
The Right

ABSTRACT A mutant of Neurospora crassa with an altered repressible acid phosphatase has been isolated. The enzyme is much more thermolabile than that of wild type, and has an increased Michaelis constant. Tests of allelic interactions (in partial diploids) and in vitro mixing experiments were consistent with the mutation being in the structural gene for the enzyme. This gene, pho-3, was found to be located in the right arm of Linkage Group IV (LG IV). Thus, pho-3 and the structural gene for repressible alkaline phosphatase, pho-2 (LG V), map in separate linkage groups and cannot be part of the same operon. Neither of these structural genes is linked to the known regulatory genes, nuc-1 (LG I), nuc-2 (LG II), and preg (LG II).

scholarly journals Chromosome rearrangements recovered following transformation of Neurospora crassa.

Genetics ◽  
1993 ◽  
Vol 134 (3) ◽  
pp. 729-736 ◽  
Author(s):  
D D Perkins ◽  
J A Kinsey ◽  
D K Asch ◽  
G D Frederick
Keyword(s):  
Neurospora Crassa ◽  
Southern Hybridization ◽  
Chromosome Rearrangements ◽  
Linkage Groups ◽  
Event Sequences ◽  
Stable Transformants

Abstract New chromosome rearrangements were found in 10% or more of mitotically stable transformants. This was shown for transformations involving a variety of different markers, vectors and recipient strains. Breakpoints were randomly distributed among the seven linkage groups. Controls using untransformed protoplasts of the same strains contained almost no rearrangements. A study of molecularly characterized Am+ transformants showed that rearrangements are frequent when multiple ectopic integration events have occurred. In contrast, rearrangements are absent or infrequent when only the resident locus is restored to am+ by a homologous event. Sequences of the transforming vector were genetically linked to breakpoints in 6 of 10 translocations that were examined using Southern hybridization or colony blots.

scholarly journals Cloning and characterization of centromeric DNA from Neurospora crassa.

1994 ◽  
Vol 14 (2) ◽  
pp. 1510-1519 ◽  
Author(s):  
M Centola ◽  
J Carbon
Keyword(s):  
Sequence Analysis ◽  
Linkage Group ◽  
Neurospora Crassa ◽  
Repetitive Sequences ◽  
Linkage Groups ◽  
Specific Sequence ◽  
Centromeric Dna ◽  
Southern Blots

The centromere locus from linkage group VII of Neurospora crassa has been cloned, characterized, and physically mapped. The centromeric DNA is contained within a 450-kb region that is recombination deficient, A+T-rich, and contains repetitive sequences. Repetitive sequences from within this region hybridize to a family of repeats located at or near centromeres in all seven linkage groups of N. crassa. Genomic Southern blots and sequence analysis of these repeats revealed a unique centromere structure containing a divergent family of centromere-specific repeats. The predominantly transitional differences between copies of the centromere-specific sequence repeats and their high A+T content suggest that their divergence was mediated by repeat-induced point (RIP) mutations.

Cloning and characterization of centromeric DNA from Neurospora crassa

1994 ◽  
Vol 14 (2) ◽  
pp. 1510-1519
Author(s):  
M Centola ◽  
J Carbon
Keyword(s):  
Sequence Analysis ◽  
Linkage Group ◽  
Neurospora Crassa ◽  
Repetitive Sequences ◽  
Linkage Groups ◽  
Specific Sequence ◽  
Centromeric Dna ◽  
Southern Blots

The centromere locus from linkage group VII of Neurospora crassa has been cloned, characterized, and physically mapped. The centromeric DNA is contained within a 450-kb region that is recombination deficient, A+T-rich, and contains repetitive sequences. Repetitive sequences from within this region hybridize to a family of repeats located at or near centromeres in all seven linkage groups of N. crassa. Genomic Southern blots and sequence analysis of these repeats revealed a unique centromere structure containing a divergent family of centromere-specific repeats. The predominantly transitional differences between copies of the centromere-specific sequence repeats and their high A+T content suggest that their divergence was mediated by repeat-induced point (RIP) mutations.

GENETICS OF 5-FLUORODEOXYURIDINE-RESISTANT MUTANTS OF NEUROSPORA CRASSA

1973 ◽  
Vol 15 (4) ◽  
pp. 831-844 ◽  
Author(s):  
G. R. Hoffmann ◽  
H. V. Malling ◽  
T. J. Mitchell
Keyword(s):  
Neurospora Crassa ◽  
Ultraviolet Light ◽  
Resistance Genes ◽  
Linkage Studies ◽  
Linkage Groups ◽  
Mechanisms Of Resistance ◽  
Growth Tube ◽  
Light Resistance ◽  
Resistant Mutants

Mutants resistant to inhibitory concentrations of 5-fluorodeoxyuridine (FdUrd) were induced by ultraviolet light. Resistance was demonstrated by growth-tube experiments and by plating efficiencies in the presence and in the absence of FdUrd. Linkage studies involving five mutants revealed the existence of at least two loci conferring resistance to the inhibitor. These loci, designated fdu-1 and fdu-2, were assigned to Linkage Groups VII and IV, respectively. Both resistance genes are recessive to their sensitive alleles in heterokaryons. Resistance to FdUrd is stable both in the presence and in the absence of the inhibitor. Possible mechanisms of resistance to FdUrd are discussed.

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 ISOLATION AND CHARACTERIZATION OF LIGHT-INSENSITIVE MUTANTS OF NEUROSPORA CRASSA

Genetics ◽  
1983 ◽  
Vol 104 (1) ◽  
pp. 11-21
Author(s):  
John Paietta ◽  
Malcolm L Sargent
Keyword(s):  
Genetic Analysis ◽  
Neurospora Crassa ◽  
Blue Light ◽  
Light Sensitivity ◽  
Phase Shifting ◽  
Nuclear Genes ◽  
Wild Type ◽  
Linkage Groups ◽  
Isolation And Characterization

ABSTRACT As part of a genetic analysis of blue light photoreception in Neurospora, three mutants were isolated that do not exhibit photosuppression of circadian conidiation, i.e., they show periodic conidiation in constant light. The mutations have been given the designations lis-1, lis-2 and lis-3 ("light insensitive"). The three mutations segregate as single nuclear genes, are nonallelic and are recessive to wild type in heterokaryon tests. The linkage groups of the mutations are as follows: lis-1, I; lis-2, VI; and lis-3, V. The light -insensitive phenotype of the mutants is restricted to the photosuppression response; other responses such as photoinduced phase shifting of the conidiation rhythm and photoinduced carotenogenesis are not altered. The physiological or biochemical defects of the mutants have not been established, but they are not similar to previous reported cases (i.e., rib and poky) in which a reduction in light sensitivity has been observed.

An electrophoretic karyotype of Neurospora crassa

1988 ◽  
Vol 8 (4) ◽  
pp. 1469-1473 ◽  
Author(s):  
M J Orbach ◽  
D Vollrath ◽  
R W Davis ◽  
C Yanofsky
Keyword(s):  
Neurospora Crassa ◽  
Electric Fields ◽  
Gel Electrophoresis ◽  
Electrophoretic Karyotype ◽  
Dna Molecules ◽  
Linkage Groups ◽  
Homogeneous Electric Field ◽  
Chromosomal Dna ◽  
Molecular Karyotype ◽  
Electrophoresis System

A molecular karyotype of Neurospora crassa was obtained by using an alternating-field gel electrophoresis system which employs contour-clamped homogeneous electric fields. The migration of all seven N. crassa chromosomal DNAs was defined, and five of the seven molecules were separated from one another. The estimated sizes of these molecules, based on their migration relative to Schizosaccharomyces pombe chromosomal DNA molecules, are 4 to 12.6 megabases. The seven linkage groups were correlated with specific chromosomal DNA bands by hybridizing transfers of contour-clamped homogeneous electric field gels with radioactive probes specific to each linkage group. The mobilities of minichromosomal DNAs generated from translocation strains were also examined. The methods used for preparation of chromosomal DNA molecules and the conditions for their separation should be applicable to other filamentous fungi.

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