scholarly journals RECOVERY AND CHARACTERIZATION OF TEMPERATURE-SENSITIVE MUTATIONS AFFECTING ADULT VIABILITY IN DROSOPHILA MELANOGASTER

Genetics ◽  
1986 ◽  
Vol 113 (2) ◽  
pp. 367-389
Author(s):  
Theodore Homyk ◽  
Donald A R Sinclair ◽  
David T L Wong ◽  
Thomas A Grigliatti
Keyword(s):  
Temperature Shift ◽  
The Other ◽  
Temperature Sensitive ◽  
Cell Type ◽  
Lethal Mutations ◽  
Preimaginal Development ◽  
Depth Analysis ◽  
Mosaic Analysis ◽  
Developmental Analysis

ABSTRACT Temperature-sensitive (ts) autonomous cell-lethal mutations have been used extensively to study important developmental phenomena, such as pattern formation, in Drosophila. Their utility would be enhanced considerably if it were possible to establish which cell type is primarily affected by each lesion. To facilitate such an approach we have isolated and characterized 21 EMS- induced X-linked adult-lethal (adl) mutants, 16 of which are ts. Most of these lesions also elicit ts lethal effects during preimaginal development. They represent 19 different loci distributed randomly along the X chromosome. The general properties of these mutations are described. In addition, results of an in-depth analysis (focus mapping and, in some cases, temperature shift and heat-pulse studies) of four strains, adl-1ts  1, sesE, adl-2ts  1 and rex are reported. Two major temperature-sensitive periods (TSPs) of adl-1 lethality were resolved: one during the second half of embryogenesis and the other coinciding with pupariation. Mosaic analysis revealed separate mesodermal foci for leg paralysis. Developmental analysis of adl-1 embryos suggest that the adl-1 product may be required for maintenance of muscle tissue. Two discrete TSPs of sesE lethality exist: one during the second instar and the other extending from late third instar to early pupation. Mosaic analysis of sesE lethality resolved a pair of neural foci, each of which appears to incorporate three separate foci for leg paralysis. Mosaic analysis of adl-2ts  1 revealed the existence of paired lethal foci that appear to map to the vicinity of the subesophageal ganglion. Analysis of rex mosaics resolved separate mesodermal foci for leg paralysis.

Isolation and characterization of a variant myoblast cell line that is temperature sensitive for differentiation

1988 ◽  
Vol 8 (6) ◽  
pp. 2335-2341
Author(s):  
R J Akhurst ◽  
N B Flavin ◽  
J Worden
Keyword(s):  
Cell Line ◽  
Progenitor Cell ◽  
Temperature Shift ◽  
Temperature Sensitive ◽  
Isolation And Characterization ◽  
New Variant ◽  
Myoblast Cell Line ◽  
Myoblast Cell ◽  
Progenitor Cell Line

A new variant rat myogenic cell line, ts485, was isolated by subcloning the cell line ts3b2 (H. T. Nguyen, R. M. Medford, and B. Nadal-Ginard, Cell 34:281-293, 1983). Unlike the progenitor cell line, ts485 was thermosensitive for differentiation. Experiments with conditioned medium suggested that diffusible extracellular factors were not involved in dictating the differential phenotypes of ts485 cells cultured at the permissive and nonpermissive temperatures. Temperature shift experiments performed on cultures of ts485 cells indicated that the temperature-sensitive lesion was in a factor active during the growth phase and required to trigger a cascade of events leading to terminal differentiation.

scholarly journals Isolation and characterization of a variant myoblast cell line that is temperature sensitive for differentiation.

1988 ◽  
Vol 8 (6) ◽  
pp. 2335-2341 ◽  
Author(s):  
R J Akhurst ◽  
N B Flavin ◽  
J Worden
Keyword(s):  
Cell Line ◽  
Progenitor Cell ◽  
Temperature Shift ◽  
Temperature Sensitive ◽  
Isolation And Characterization ◽  
New Variant ◽  
Myoblast Cell Line ◽  
Myoblast Cell ◽  
Progenitor Cell Line

A new variant rat myogenic cell line, ts485, was isolated by subcloning the cell line ts3b2 (H. T. Nguyen, R. M. Medford, and B. Nadal-Ginard, Cell 34:281-293, 1983). Unlike the progenitor cell line, ts485 was thermosensitive for differentiation. Experiments with conditioned medium suggested that diffusible extracellular factors were not involved in dictating the differential phenotypes of ts485 cells cultured at the permissive and nonpermissive temperatures. Temperature shift experiments performed on cultures of ts485 cells indicated that the temperature-sensitive lesion was in a factor active during the growth phase and required to trigger a cascade of events leading to terminal differentiation.

scholarly journals CHARACTERIZATION OF TEMPERATURE-SENSITIVE MUTANTS OF MEASLES VIRUS: TEMPERATURE-SHIFT EXPERIMENT

1975 ◽  
Vol 28 (4) ◽  
pp. 223-229 ◽  
Author(s):  
YUKIO YAMAZI ◽  
FRANCIS L. BLACK ◽  
HIROSHI HONDA ◽  
YUKO TODOME ◽  
MASARU SUGANUMA ◽  
...  
Keyword(s):  
Measles Virus ◽  
Temperature Shift ◽  
Temperature Sensitive ◽  
Temperature Sensitive Mutants ◽  
Shift Experiment

scholarly journals GENETIC AND DEVELOPMENTAL ANALYSIS OF A TEMPERATURE-SENSITIVE MINUTE MUTATION OF DROSOPHILA MELANOGASTER

Genetics ◽  
1981 ◽  
Vol 97 (3-4) ◽  
pp. 581-606 ◽  
Author(s):  
Donald A R Sinclair ◽  
David T Suzuki ◽  
Thomas A Grigliatti
Keyword(s):  
Larval Instar ◽  
Temperature Shift ◽  
Heat Pulse ◽  
Sensitive Period ◽  
Temperature Sensitive ◽  
Direct Effects ◽  
First Instar ◽  
Reciprocal Temperature ◽  
Morphological Defects ◽  
Developmental Analysis

ABSTRACT A temperature-sensitive (ts) third chromosome Minute (M) mutation, designated Q-III, has been recovered and characterized. Q-III heterozygotes raised at 29" exhibit all of the dominant traits of M mutants including small bristles, rough eyes, prolonged development, reduced viability 2nd interactions with several unrelated mutations. Q-III homozygotes raised at 29° are lethal; death occurs primarily during the first larval instar. When raised at 22°, Q-Ill heterozygotes are phenotypically normal and Q-III homozygotes display moderate Mtraits. In addition, Q-IIIelicits ts sterility and maternal-effect lethality. As it true of Mlesions, the dominant traits of Q-111 are not expressed in triploid females raised at 29°. Complementation tests suggest that Q-III is a ts allele of M(3)LS4, which is located in 3L near the centromere.——Reciprocal temperature-shift experiments revealed that the temperature-sensitive period (TSP) of Q-111 lethality is polyphasic, extending from the first instar to the latter half of pupation. Heat-pulse experiments further resolved this into two post-embryonic TSPs: one occurring during the latter half of the second larval instar, and the other extending from the larval/pupal boundary to the second half of pupation. In addition, heat pulses elicited a large number of striking adult phenotypes in Q-III individuals. These included pattern alterations such as deficiencies and duplications and cther morphological defects in structures produced by the eye-antennal, leg, wing and genital imaginal discs and the abdominal histoblasts. Each defect or pattern alteration is associated with a specific TSP during development.——We favor the interpretation that most of the major Q-III defects, particularly the structural duplications and deficiencies, result from temperature-induced cell death in mitotically active imaginal anlagen, while the small macrochaete phene probably results from the direct effects of Q-III on bristle synthesis. The hypothesis that the Q-III locus specifices a component required for protein synthesis is discussed, and it is concluded that this hypothesis can account for the pleiotropy of Q-III, and that perhaps it can be extended to M loci in general.

scholarly journals Cycloheximide-resistant temperature-sensitive lethal mutations of Saccharomyces cerevisiae.

Genetics ◽  
1988 ◽  
Vol 119 (2) ◽  
pp. 303-315
Author(s):  
J H McCusker ◽  
J E Haber
Keyword(s):  
Inhibitory Concentration ◽  
Temperature Sensitive ◽  
Nonpermissive Temperature ◽  
Wild Type ◽  
Lethal Mutations ◽  
New Methods ◽  
Similar Temperature ◽  
Complementation Groups ◽  
Wild Type Yeast

Abstract We describe the isolation and preliminary characterization of a set of pleiotropic mutations resistant to the minimum inhibitory concentration of cycloheximide and screened for ts (temperature-sensitive) growth. These mutations fall into 22 complementation groups of cycloheximide resistant ts lethal mutations (crl). None of the crl mutations appears to be allelic with previously isolated mutations. Fifteen of the CRL loci have been mapped. At the nonpermissive temperature (37 degrees), these mutants arrest late in the cell cycle after several cell divisions. Half of these mutants are also unable to grow at very low temperatures (5 degrees). Although mutants from all of the 22 complementation groups exhibit similar temperature-sensitive phenotypes, an extragenic suppressor of the ts lethality of crl3 does not relieve the ts lethality of most other crl mutants. A second suppressor mutation allows crl10, crl12, and crl14 to grow at 37 degrees but does not suppress the ts lethality of the remaining crl mutants. We also describe two new methods for the enrichment of auxotrophic mutations from a wild-type yeast strain.

Isolation and partial characterization of a human adenovirus type 4 temperature-sensitive mutant (Mastadenovirus h 4 tsl)

1984 ◽  
Vol 30 (2) ◽  
pp. 135-141 ◽  
Author(s):  
Linda M. Mofford ◽  
R. G. Marusyk
Keyword(s):  
Selection Procedure ◽  
Temperature Shift ◽  
Human Adenovirus ◽  
Adenovirus Type ◽  
Temperature Sensitive ◽  
Penton Base ◽  
Virus Stock ◽  
Ts Mutant ◽  
Viruslike Particles

A random selection procedure was used to isolate a temperature-sensitive (ts) mutant of human adenovirus type 4 (Mastadenovirus h 4 tsl) from nitrous acid mutagenized virus stock. The mutant displayed restricted growth at the nonpermissive temperature of 39 °C. Analysis of the mutant grown at 39 °C, by two-dimensional immunoelectrophoretic analysis, showed the mutant to be defective in the expression of the penton base and fibre structural components. The mutant was, however, capable of synthesizing immunologically reactive hexon components. Temperature-shift experiments revealed detectable fibre and penton to be present following shift-down from 39 to 32 °C. Time-sequence analysis of shift-down experiments suggested a possible defect in processing of the components, as indicated by an increase of immunologically detectable penton base. The ability of the mutant to assemble viruslike particles at 39 °C was confirmed by electron microscopy. Though the particles assembled appeared as mature virions, crystalline arrays of packed particles were less in number and somewhat smaller in size than those observed at 32 °C.

Conditional defect in mRNA 3' end processing caused by a mutation in the gene for poly(A) polymerase

1992 ◽  
Vol 12 (7) ◽  
pp. 3297-3304
Author(s):  
D Patel ◽  
J S Butler
Keyword(s):  
Temperature Shift ◽  
Temperature Sensitive ◽  
Single Mutation ◽  
Mrna Levels ◽  
Endonucleolytic Cleavage ◽  
Normal Site ◽  
Apparent Loss ◽  
And Function

Maturation of most eukaryotic mRNA 3' ends requires endonucleolytic cleavage and polyadenylation of precursor mRNAs. To further understand the mechanism and function of mRNA 3' end processing, we identified a temperature-sensitive mutant of Saccharomyces cerevisiae defective for polyadenylation. Genetic analysis showed that the polyadenylation defect and the temperature sensitivity for growth result from a single mutation. Biochemical analysis of extracts from this mutant shows that the polyadenylation defect occurs at a step following normal site-specific cleavage of a pre-mRNA at its polyadenylation site. Molecular cloning and characterization of the wild-type allele of the mutated gene revealed that it (PAP1) encodes a previously characterized poly(A) polymerase with unknown RNA substrate specificity. Analysis of mRNA levels and structure in vivo indicate that shift of growing, mutant cells to the nonpermissive temperature results in the production of poly(A)-deficient mRNAs which appear to end at their normal cleavage sites. Interestingly, measurement of the rate of protein synthesis after the temperature shift shows that translation continues long after the apparent loss of polyadenylated mRNA. Our characterization of the pap1-1 defect implicates this gene as essential for mRNA 3' end formation in S. cerevisiae.

scholarly journals Isolation and characterization of chromosome-gain and increase-in-ploidy mutants in yeast.

Genetics ◽  
1993 ◽  
Vol 135 (3) ◽  
pp. 677-691 ◽  
Author(s):  
C S Chan ◽  
D Botstein
Keyword(s):  
Spindle Pole Body ◽  
Temperature Shift ◽  
Spindle Pole ◽  
Temperature Sensitive ◽  
Chromosome Gain ◽  
Recessive Mutations ◽  
Isolation And Characterization ◽  
Complementation Groups ◽  
Bud Growth

Abstract We have developed a colony papillation assay for monitoring the copy number of genetically marked chromosomes II and III in Saccharomyces cerevisiae. The unique feature of this assay is that it allows detection of a gain of the marked chromosomes even if there is a gain of the entire set of chromosomes (increase-in-ploidy). This assay was used to screen for chromosome-gain or increase-in-ploidy mutants. Five complementation groups have been defined for recessive mutations that confer an increase-in-ploidy (ipl) phenotype, which, in each case, cosegregates with a temperature-sensitive growth phenotype. Four new alleles of CDC31, which is required for spindle pole body duplication, were also recovered from this screen. Temperature-shift experiments with ipl1 cells show that they suffer severe nondisjunction at 37 degrees. Similar experiments with ipl2 cells show that they gain entire sets of chromosomes and become arrested as unbudded cells at 37 degrees. Molecular cloning and genetic mapping show that IPL1 is a newly identified gene, whereas IPL2 is allelic to BEM2, which is required for normal bud growth.

scholarly journals Requirements for hedgehog, a segmental polarity gene, in patterning larval and adult cuticle of Drosophila.

Genetics ◽  
1988 ◽  
Vol 120 (4) ◽  
pp. 1061-1072 ◽  
Author(s):  
J Mohler
Keyword(s):  
Temperature Shift ◽  
Ventral Surface ◽  
Activity Period ◽  
Temperature Sensitive ◽  
Posterior Compartment ◽  
Shift Analysis ◽  
Mosaic Analysis ◽  
Sensitive Allele ◽  
Anteroposterior Polarity ◽  
Polarity Gene

Abstract Mutations of the hedgehog gene are generally embryonic lethal, resulting in a lawn of denticles on the ventral surface. In strong alleles, no segmentation is obvious and the anteroposterior polarity of ventral denticles is lost. Temperature shift analysis of a temperature-sensitive allele indicates an embryonic activity period for hedgehog between 2.5 and 6 hr of embryonic development (at 25 degrees) and a larval/pupal period from 4 to 7 days of development (at 25 degrees). Mosaic analysis of hedgehog mutations in the adult cuticle indicates a series of defined defects associated with the failure of appropriate hedgehog expression. In particular, defects in the distal portions of the legs and antenna occur in association with homozygous hedgehog clones in the posterior compartment of those structures. Because the defects are associated with homozygous clones, but are not co-extensive, a type of "domineering" nonautonomy is proposed for the activity of the hedgehog gene.

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