Stomatogenesis in Paramecium tetraurelia: genetics and phenotypes of mutants affecting the development of the oral apparatus

1987 ◽  
Vol 65 (9) ◽  
pp. 2177-2187 ◽  
Author(s):  
Lai-Wa Tam ◽  
Stephen F. Ng
Keyword(s):  
Cell Division ◽  
Ultraviolet Irradiation ◽  
Buccal Cavity ◽  
The Other ◽  
Temperature Sensitive ◽  
Paramecium Tetraurelia ◽  
Single Mutant ◽  
Temperature Sensitive Mutants ◽  
Recessive Genes ◽  
Acting In Concert

Seven temperature-sensitive mutants of Paramecium tetraurelia, in which the development of the oral apparatus was affected, were recovered from mutagenesis with N-methyl-N′-nitro-N-nitrosoguanidine and ultraviolet irradiation and analysed. Five of them (short-1, buccalless-1, crook-1, monster-1, monster-2) were shown to possess single mutant recessive genes (designated sh1, bu1, cr1, mo1, and mo2, respectively). The other two, short-2 and short-3, were probably of the same mutagenic origin, which involved two linked recessive loci acting in concert. The short mutants are characterized by reduction in the length of the buccal cavity and oral membranelles and disruption of the organization of the membranelles. The crook mutant shows extra curvature and lengthening of the oral membranelles. The buccalless mutant exhibits loss of the buccal cavity, in addition to the absence, shortening, or disruption of the organization of oral membranelles. The monsters develop abnormal oral apparatuses and abnormalities in cell division giving rise to monstrous cells. All of these mutations are pleiotropic in expression. While the genes for short-1 and crook-1 affect stomatogenesis in the asexual and sexual cycles to similar extents, the other five mutants exhibit defects only in asexual stomatogenesis. The developmental interests of these mutants are discussed.

Temperature-sensitive mutations affecting cortical morphogenesis and cell division in Paramecium tetraurelia

1982 ◽  
Vol 60 (10) ◽  
pp. 2296-2308 ◽  
Author(s):  
Donald Jones ◽  
James D. Berger
Keyword(s):  
Cell Division ◽  
Cell Surface ◽  
Posterior Part ◽  
Gene Mutations ◽  
Temperature Sensitive ◽  
Basal Bodies ◽  
Paramecium Tetraurelia ◽  
Fission Process ◽  
Daughter Cells ◽  
Recessive Genes

Nine temperature-sensitive gene mutations affecting cellular morphogenesis were analysed and shown to be single recessive genes. Their phenotypes fall into three classes: small mutants (sm) which interfere with cell surface and basal body proliferation to produce short cells; defective fission zone mutants (dfz) which do not form a complete fission zone during cell division; and defective constriction mutants (dc) which form a normal fission zone, but do not constrict properly. In sm2 cells there is a reduction in the number of basal bodies and in the amount of cell surface produced preceding fission. This results in the production of truncated daughter cells in which most of the normal structures of either the anterior or posterior part of the cell are highly reduced or missing. Production of basal bodies in gullet primordia is also abnormal. The dfz mutants act early in the fission process to block the formation of the fission zone which precedes the formation of the fission furrow. The dc mutations act later in the fission process and lead to failure of daughter cell separation. One mutant, dc3, also shows slightly reduced proliferation of cell surface. This defect occurs prior to fission.

Mutational blockage of DNA synthesis in Paramecium tetraurelia

1976 ◽  
Vol 54 (12) ◽  
pp. 2089-2097 ◽  
Author(s):  
E. L. Peterson ◽  
J. D. Berger
Keyword(s):  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Paramecium Tetraurelia ◽  
Selection System ◽  
Replication Process ◽  
Temperature Sensitive Mutants ◽  
Fold Enrichment ◽  
Comparison Of Experiments

One hundred and ninety-eight temperature-sensitive mutants of Paramecium tetraurelia were isolated after nitrosoguanidine mutagenesis. In some experiments, mutants were recovered with the aid of a bromouracil (BU) selection system. Fifty-six mutants showed cessation of cell division within one cell cycle at the restrictive temperature and were designated ts-0. Fourteen of the ts-0's showed a greater than 90% reduction in rnacronuclear deoxyribonucleic acid (DNA) synthesis at the restrictive temperature. Two ts-0. DNA-defective lines continued protein synthesis at greater than 50% the normal rate after arrest of DNA synthesis. Hence, these two mutants may be directly affected in the replication process itself. The two mutants are allelic and, in addition, a third 'leaky' allele was recovered. Comparison of experiments in which either BU selection or no selection was employed shows that a greater than 10-fold enrichment for ts mutants resulted from BU selection.

Using fast-acting temperature-sensitive mutants to study cell division in Caenorhabditis elegans

2017 ◽  
pp. 283-306 ◽  
Author(s):  
T. Davies ◽  
S. Sundaramoorthy ◽  
S.N. Jordan ◽  
M. Shirasu-Hiza ◽  
J. Dumont ◽  
...  
Keyword(s):  
Cell Division ◽  
Caenorhabditis Elegans ◽  
Temperature Sensitive ◽  
Temperature Sensitive Mutants ◽  
Fast Acting

scholarly journals Two temperature-sensitive mutants of Saccharomyces cerevisiae with altered expression of mating-type functions.

1983 ◽  
Vol 96 (6) ◽  
pp. 1592-1600 ◽  
Author(s):  
T R Manney ◽  
P Jackson ◽  
J Meade
Keyword(s):  
Saccharomyces Cerevisiae ◽  
The Other ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Altered Expression ◽  
Temperature Sensitive Mutants ◽  
Sporulation Efficiency ◽  
Mating Efficiency ◽  
Sensitive Allele ◽  
Two Temperature

Two mutants of Saccharomyces cerevisiae have been isolated from normal haploid MAT alpha strains and characterized as having temperature-sensitive, pleiotropic phenotypes for functions associated with mating. At the permissive temperature, 23 degrees C, they were found to behave as normal MAT alpha haploids with respect to mating efficiency, sporulation in diploids formed with MAT a strains, secretion of alpha-factor, and failure to secrete the MATa-specific products, a-factor and Barrier. At higher temperatures they were found to decline in mating and sporulation efficiency and to express the a-specific functions. Genetic analysis established that one of these mutants, PE34, carries a temperature-sensitive allele of the MAT alpha 2 gene and that the other, PD7, carries a temperature-sensitive allele of the TUP1 gene.

scholarly journals A genetic map of several mutations affecting the mucopeptide layer ofEscherichia coli

1972 ◽  
Vol 20 (1) ◽  
pp. 65-74 ◽  
Author(s):  
H. J. W. Wijsman
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Fine Structure ◽  
Cell Division ◽  
Genetic Map ◽  
Genetic Relationship ◽  
Ofescherichia Coli ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Temperature Sensitive Mutants

SUMMARYSeveral temperature-sensitive mutants ofEscherichia coliwere isolated which lyse at the restrictive temperature. Some of these possess a biochemically defined lesion in cell-wall mucopeptide synthesis. Three genes, termedmurC, EandF, have been localized between theaziandleumarkers. From transductional data a fine structure map was constructed of themurmutations, establishing the order of the genes. The genetic relationship between these cell wall genes and neighbouring genes involved in cell division is discussed.

scholarly journals THE SELECTION OF AMBER MUTATIONS IN GENES REQUIRED FOR COMPLETION OF START, THE CONTROLLING EVENT OF THE CELL DIVISION CYCLE OF S. CEREVISIAE

Genetics ◽  
1980 ◽  
Vol 95 (3) ◽  
pp. 579-588 ◽  
Author(s):  
Steven I Reed
Keyword(s):  
Cell Division ◽  
Genetic Analysis ◽  
Cell Division Cycle ◽  
Class I ◽  
Temperature Sensitive ◽  
Temperature Sensitive Mutants ◽  
Amber Suppressor ◽  
Selection Of

ABSTRACT Using a modification of a procedure developed for the isolation of temperature-sensitive mutants defective in the start event of cell division, amber mutations were obtained for two Class-I start genes, cdc28 and cdc37. Genetic analysis demonstrated that co-segregation of an amber suppressor with such alleles was required for viability of spores subsequent to meiosis. These mutations are expected to be useful in the identification of the molecular products of the genes cdc28 and cdc37.

scholarly journals Causal relations among cell cycle processes in Tetrahymena pyriformis. An analysis employing temperature-sensitive mutants.

1976 ◽  
Vol 71 (1) ◽  
pp. 242-260 ◽  
Author(s):  
J Frankel ◽  
L M Jenkins ◽  
L E DeBault
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Dna Synthesis ◽  
Tetrahymena Pyriformis ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Developmental Pathway ◽  
Temperature Sensitive Mutants ◽  
Oral Development ◽  
Macronuclear Division

Utilization of temperature-sensitive mutants of Tetrahymena pyriformis affected in cell division or developmental pathway selection has permitted elucidation of causal dependencies interrelating micronuclear and macronuclear replication and division, oral development, and cytokinesis. In those mutants in which cell division is specifically blocked at restrictive temperatures, micronuclear division proceeds with somewhat accelerated periodicity but maintains normal coupling to predivision oral development. Macronuclear division is almost totally suppressed in an early acting mutant (mola) that prevents formation of the fission zone, and is variably affected in other mutants (such as mo3) that allow the fission zone to form but arrest constriction. However, macronuclear DNA synthesis can proceed for about four cycles in the nondividing mutant cells. A second class of mutants (psm) undergoes a switch of developmental pathway such that cells fail to enter division but instead repeatedly carry out an unusual type of oral replacement while growing in nutrient medium at the restrictive temperature. Under these circumstances no nuclei divide, yet macronuclear DNA accumulation continues. These results suggest that (a) macronuclear division is stringently affected by restriction of cell division, (b) micronuclear division and replication can continue in cells that are undergoing the type of oral development that is characteristic of division cycles, and (c) macronuclear DNA synthesis can continue in growing cells regardless of their developmental status. The observed relationships among events are consistent with the further suggestion that the cell cycle in this organism may consist of separate clusters of events. with a varying degree of coupling among clusters. A minimal model of the Tetrahymena cell cycle that takes these phenomena into account is suggested.

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