scholarly journals AN ACETYLCHOLINESTERASE-DEFICIENT MUTANT OF THE NEMATODE CAENORHABDITIS ELEGANS

Genetics ◽  
1981 ◽  
Vol 97 (2) ◽  
pp. 261-279 ◽  
Author(s):  
Carl D Johnson ◽  
John G Duckett ◽  
Joseph G Culotti ◽  
Robert K Herman ◽  
Philip M Meneely ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Gene Dosage ◽  
Sodium Deoxycholate ◽  
Molecular Forms ◽  
Kinetic Properties ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
Class A ◽  
Mutant Strains ◽  
The Right

ABSTRACT Within a set of five separable molecular forms of acetylcholinesterase found in the nematode Caenorhabditis elegans, previously reported differences in kinetic properties identify two classes, A and B, likely to be under separate genetic control. Using differences between these classes in sensitivity to inactivation by sodium deoxycholate, a screening procedure was devised to search for mutants affected only in class A forms. Among 171 previously isolated behavioral and morphological mutant strains examined by this procedure, one (PR946) proved to be of the expected type, exhibiting a selective deficiency of class A acetylcholinesterase forms. Although originally isolated because of its uncoordinated behavior, this strain was subsequently shown to harbor mutations in two genes; one in the previously identified gene unc-3, accounting for its behavior, and one in a newly identified gene, ace-1, accounting for its selective acetylcholinesterase deficiency. Derivatives homozygous only for the ace-1 mutation also lacked class A acetylcholinesterase forms, but were behaviorally and developmentally indistinguishable from wild type. The gene ace-1 has been mapped near the right end of the X chromosome. Gene dosage experiments suggest that it may be a structural gene for a component of class A acetylcholinesterase forms.

scholarly journals CHOLINE ACETYLTRANSFERASE-DEFICIENT MUTANTS OF THE NEMATODE CAENORHABDITIS ELEGANS

Genetics ◽  
1984 ◽  
Vol 106 (2) ◽  
pp. 227-248
Author(s):  
James B Rand ◽  
Richard L Russell
Keyword(s):  
Caenorhabditis Elegans ◽  
Choline Acetyltransferase ◽  
Cholinesterase Inhibitors ◽  
Gene Dosage ◽  
Enzyme Level ◽  
Group Iv ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
Wild Type Enzyme ◽  
Single Complex

ABSTRACT We have identified five independent allelic mutations, defining the gene cha-1, that result in decreased choline acetyltransferase (ChAT) activity in Caenorhabditis elegans. Four of the mutant alleles, when homozygous, lead to ChAT reductions of>98%, as well as recessive phenotypes of uncoordinated behavior, small size, slow growth and resistance to cholinesterase inhibitors. Animals homozygous for the fifth allele retain approximately 10% of the wild-type enzyme level; purified enzyme from this mutant has altered K  m values for both choline and acetyl-CoA and is more thermolabile than the wild-type enzyme. These qualitative alterations, together with gene dosage data, argue that cha-1 is the structural gene for ChAT. cha-1 has been mapped to the left arm of linkage group IV and is within 0.02 map unit of the gene unc-17, mutant alleles of which lead to all of the phenotypes of cha-1 mutants except for the ChAT deficiency. Extensive complementation studies of cha-1 and unc-17 alleles reveal a complex complementation pattern, suggesting that both loci may be part of a single complex gene.

Three Mutants That Extend Both Mean and Maximum Life Span of the Nematode, Caenorhabditis elegans , Define the age-1 Gene

2002 ◽  
Vol 2002 (38) ◽  
Author(s):  
David B. Friedman ◽  
Thomas E. Johnson
Keyword(s):  
Caenorhabditis Elegans ◽  
Life Span ◽  
Pleiotropic Effect ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
Maximum Life Span ◽  
Gerontological Society ◽  
Recessive Mutations ◽  
Mutant Strains ◽  
Independent Mutation

Long-lived mutants in the nematode Caenorhabditis elegans have been studied to determine if the mutations responsible for extended life were allelic. Three of four mutant strains studied (MK31, MK542, MK546) contain recessive mutations that significantly lengthen life; MK542 and MK546 consistently fail to complement the long life phenotype of age-1 and are therefore allelic. MK31, although longer lived than wild type, is equivocal, in some cases failing to complement age-1 but not in others. All three long-lived strains have reduced hermaphrodite self-fertility and also fail to complement for this presumed pleiotropic effect of the age-1 mutation. Each of these three strains also contains an independent mutation at unc-31 IV. Since the mutants were isolated in the same mutant hunt (Klass, 1983) using protocols that did not guarantee independence, the mutations cannot be assumed to be independently isolated. Copyright (c) The Gerontological Society of America. Reproduced by permission of the publisher. David B. Friedman, Thomas E. Johnson, Three Mutants That Extend Both Mean and Maximum Life Span of the Nematode, Caenorhabditis elegans , Define the age-1 Gene. J. Gerontol. 43 , B102-B109 (1988).

scholarly journals β-GLUCURONIDASE MUTANTS OF THE NEMATODE CAENORHABDITIS ELEGANS

Genetics ◽  
1986 ◽  
Vol 112 (3) ◽  
pp. 459-468
Author(s):  
Marisa Sebastiano ◽  
Marina D'Alessio ◽  
Paolo Bazzicalupo
Keyword(s):  
Enzyme Activity ◽  
Caenorhabditis Elegans ◽  
Complementation Group ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
Structural Locus ◽  
Glucuronidase Activity ◽  
Group I ◽  
New Gene ◽  
The Right

ABSTRACT Using a screening procedure that is based on a histochemical stain for the enzyme β-glucuronidase, we have isolated several mutants of the nematode Caenorhabditis elegans affected in β-glucuronidase activity. All of the mutations fall into one complementation group and identify a new gene, gus-1, which has been mapped on the right arm of linkage group I (LG I), 1.1 map units to the left of unc-54. The mutants have no visible phenotype, and their viabilities and fertilities are unaffected. Linked revertants of two of the mutations have been isolated. They restore enzyme activity to almost wild-type levels; the β-glucuronidase that one of the revertants produces differs from that of the wild type. We propose that gus-1 is the structural locus for β-glucuronidase.

scholarly journals The Tc5 family of transposable elements in Caenorhabditis elegans.

Genetics ◽  
1994 ◽  
Vol 137 (3) ◽  
pp. 771-781 ◽  
Author(s):  
J J Collins ◽  
P Anderson
Keyword(s):  
Caenorhabditis Elegans ◽  
High Frequency ◽  
Wild Type ◽  
Induced Mutations ◽  
Nematode Caenorhabditis Elegans ◽  
C Elegans ◽  
New Family ◽  
Mutant Strains ◽  
Transposable Genetic Elements ◽  
Size And Structure

Abstract We have identified Tc5, a new family of transposable genetic elements in the nematode Caenorhabditis elegans. All wild-type varieties of C. elegans that we examined contain 4-6 copies of Tc5 per haploid genome, but we did not observe transposition or excision of Tc5 in these strains. Tc5 is active, however, in the mut-2 mutant strain TR679. Of 60 spontaneous unc-22 mutations isolated from strain TR679, three were caused by insertion of Tc5. All three Tc5-induced mutations are unstable; revertants results from precise or nearly precise excision of Tc5. Individual Tc5 elements are similar to each other in size and structure. The 3.2-kb element is bounded by inverted terminal repeats of nearly 500 bp. Eight of the ten terminal nucleotides of Tc5 are identical to the corresponding nucleotides of Tc4. Further, both elements recognize the same target site for insertion (CTNAG) and both cause duplication of the central TNA trinucleotide upon insertion. Other than these similarities to Tc4, Tc5 is unrelated to the three other transposon families (Tc1, Tc3 and Tc4) that transpose and excise at high frequency in mut-2 mutant strains. Mechanisms are discussed by which four apparently unrelated transposon families are all affected by the same mut-2 mutation.

scholarly journals Sperm Competition in the Absence of Fertilization in Caenorhabditis elegans

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 201-208 ◽  
Author(s):  
Andrew Singson ◽  
Katherine L Hill ◽  
Steven W L’Hernault
Keyword(s):  
Caenorhabditis Elegans ◽  
Sperm Competition ◽  
Sperm Function ◽  
Sperm Precedence ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
C Elegans ◽  
Normal Sperm ◽  
Self Fertilization ◽  
Competition Assays

Abstract Hermaphrodite self-fertilization is the primary mode of reproduction in the nematode Caenorhabditis elegans. However, when a hermaphrodite is crossed with a male, nearly all of the oocytes are fertilized by male-derived sperm. This sperm precedence during reproduction is due to the competitive superiority of male-derived sperm and results in a functional suppression of hermaphrodite self-fertility. In this study, mutant males that inseminate fertilization-defective sperm were used to reveal that sperm competition within a hermaphrodite does not require successful fertilization. However, sperm competition does require normal sperm motility. Additionally, sperm competition is not an absolute process because oocytes not fertilized by male-derived sperm can sometimes be fertilized by hermaphrodite-derived sperm. These results indicate that outcrossed progeny result from a wild-type cross because male-derived sperm are competitively superior and hermaphrodite-derived sperm become unavailable to oocytes. The sperm competition assays described in this study will be useful in further classifying the large number of currently identified mutations that alter sperm function and development in C. elegans.

scholarly journals Genetic, Behavioral and Environmental Determinants of Male Longevity in Caenorhabditis elegans

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1597-1610 ◽  
Author(s):  
David Gems ◽  
Donald L Riddle
Keyword(s):  
Caenorhabditis Elegans ◽  
Life Span ◽  
Wild Type ◽  
Neuronal Function ◽  
Nematode Caenorhabditis Elegans ◽  
Wild Isolate ◽  
Young Males ◽  
C Elegans ◽  
Single Sex ◽  
Solitary Males

Abstract Males of the nematode Caenorhabditis elegans are shorter lived than hermaphrodites when maintained in single-sex groups. We observed that groups of young males form clumps and that solitary males live longer, indicating that male-male interactions reduce life span. By contrast, grouped or isolated hermaphrodites exhibited the same longevity. In one wild isolate of C. elegans, AB2, there was evidence of copulation between males. Nine uncoordinated (unc) mutations were used to block clumping behavior. These mutations had little effect on hermaphrodite life span in most cases, yet many increased male longevity even beyond that of solitary wild-type males. In one case, the neuronal function mutant unc-64(e246), hermaphrodite life span was also increased by up to 60%. The longevity of unc-4(e120), unc-13(e51), and unc-32(e189) males exceeded that of hermaphrodites by 70–120%. This difference appears to reflect a difference in sex-specific life span potential revealed in the absence of male behavior that is detrimental to survival. The greater longevity of males appears not to be affected by daf-2, but is influenced by daf-16. In the absence of male-male interactions, median (but not maximum) male life span was variable. This variability was reduced when dead bacteria were used as food. Maintenance on dead bacteria extended both male and hermaphrodite longevity.

scholarly journals Isolation, characterization and epistasis of fluoride-resistant mutants of Caenorhabditis elegans.

Genetics ◽  
1994 ◽  
Vol 136 (1) ◽  
pp. 145-154
Author(s):  
I Katsura ◽  
K Kondo ◽  
T Amano ◽  
T Ishihara ◽  
M Kawakami
Keyword(s):  
Caenorhabditis Elegans ◽  
Brood Size ◽  
Normal Growth ◽  
Fluoride Ion ◽  
Wild Type ◽  
Signal Transduction System ◽  
Nematode Caenorhabditis Elegans ◽  
C Elegans ◽  
Class 1 ◽  
Resistant Mutants

Abstract We have isolated 13 fluoride-resistant mutants of the nematode Caenorhabditis elegans. All the mutations are recessive and mapped to five genes. Mutants in three of the genes (class 1 genes: flr-1 X, flr-3 IV, and flr-4 X) are resistant to 400 micrograms/ml NaF. Furthermore, they grow twice as slowly as and have smaller brood size than wild-type worms even in the absence of fluoride ion. In contrast, mutants in the other two genes (class 2 genes: flr-2 V and flr-5 V) are only partially resistant to 400 micrograms/ml NaF, and they have almost normal growth rates and brood sizes in the absence of fluoride ion. Studies on the phenotypes of double mutants showed that class 2 mutations are epistatic to class 1 mutations concerning growth rate and brood size but hypostatic with respect to fluoride resistance. We propose two models that can explain the epistasis. Since fluoride ion depletes calcium ion, inhibits some protein phosphatases and activates trimeric G-proteins, studies on these mutants may lead to discovery of a new signal transduction system that controls the growth of C. elegans.

CAENORHABDITIS ELEGANS DEFICIENCY MAPPING

Genetics ◽  
1984 ◽  
Vol 108 (2) ◽  
pp. 331-345
Author(s):  
D Christine Sigurdson ◽  
Gail J Spanier ◽  
Robert K Herman
Keyword(s):  
Caenorhabditis Elegans ◽  
Linkage Group ◽  
Ethyl Methanesulfonate ◽  
Single Site ◽  
Crossing Over ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
Recessive Lethal ◽  
X Ray ◽  
New Mutations

ABSTRACT Six schemes were used to identify 80 independent recessive lethal deficiencies of linkage group (LG) II following X-ray treatment of the nematode Caenorhabditis elegans. Complementation tests between the deficiencies and ethyl methanesulfonate-induced recessive visible, lethal and sterile mutations and between different deficiencies were used to characterize the extents of the deficiencies. Deficiency endpoints thus helped to order 36 sites within a region representing about half of the loci on LG II and extending over about 5 map units. New mutations occurring in this region can be assigned to particular segments of the map by complementation tests against a small number of deficiencies; this facilitates the assignment of single-site mutations to particular genes, as we illustrate. Five sperm-defective and five oocyte-defective LG II sterile mutants were identified and mapped. Certain deficiency-by-deficiency complementation tests allowed us to suggest that the phenotypes of null mutations at two loci represented by visible alleles are wild type and that null mutations at a third locus confer a visible phenotype. A segment of LG II that is about 12 map units long and largely devoid of identified loci seems to be greatly favored for crossing over.

scholarly journals Altered expression of an L1-specific, O-linked cuticle surface glycoprotein in mutants of the nematode Caenorhabditis elegans.

1991 ◽  
Vol 115 (5) ◽  
pp. 1237-1247 ◽  
Author(s):  
R M Hemmer ◽  
S G Donkin ◽  
K J Chin ◽  
D G Grenache ◽  
H Bhatt ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Specific Antigen ◽  
Surface Glycoprotein ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
Altered Expression ◽  
C Elegans ◽  
Larval Stages ◽  
Sds Page ◽  
Free Living Nematode

Mouse mAb M38 was used in indirect immunofluorescence experiments to detect a stage-specific antigen on the surface of the first larval stage (L1) of the free-living nematode Caenorhabditis elegans, and to detect alterations in the apparent expression of this antigen in two distinct classes of C. elegans mutants. In previously described srf-2 and srf-3 mutants (Politz S. M., M. T. Philipp, M. Estevez, P.J. O'Brien, and K. J. Chin. 1990. Proc. Natl. Acad. Sci. USA. 87:2901-2905), the antigen is not detected on the surface of any stage. Conversely, in srf-(yj43) and other similar mutants, the antigen is expressed on the surface of the first through the fourth (L4) larval stages. To understand the molecular basis of these alterations, the antigen was characterized in gel immunoblotting experiments. After SDS-PAGE separation and transfer to nitrocellulose, M38 detected a protein antigen in extracts of wild-type L1 populations. The antigen was sensitive to digestion by Pronase and O-glycanase (endo-alpha-N-acetylgalactosaminidase), suggesting that it is an O-linked glycoprotein. This antigen was not detected in corresponding extracts of wild-type L4s or srf-2 or srf-3 L1s, but was detected in extracts of srf-(yj43) L4s. The antigen-defective phenotype of srf-3 was epistatic to the heterochronic mutant phenotype of srf-(yj43) in immunofluorescence tests of the srf-3 srf-(yj43) double mutant, suggesting that srf-(yj43) causes incorrect regulation of a pathway of antigen formation that requires wild-type srf-3 activity.

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