Molecular and genetic analysis of unc-7, a Caenorhabditis elegans gene required for coordinated locomotion.

Abstract Mutations in the Caenorhabditis elegans gene unc-7 confer an uncoordinated phenotype. Wild-type animals trace smooth, sinuous waves as they move; unc-7 mutants make irregular bends or kinks along their bodies, particularly when they move forward. The unc-7 locus has also been implicated in the nematode's response to volatile anesthetics. We have cloned unc-7 by transposon tagging: an unc-7 mutation was correlated with the insertion of the transposon Tc1, and reversion of the mutant phenotype was correlated with loss of the Tc1 element. We have physically mapped the region flanking the sites of Tc1 insertion and identified DNA rearrangements corresponding to eight additional unc-7 alleles. Northern analysis indicates that a 2.7-kb unc-7 message is present in all developmental stages but is most abundant in L1-L3 larvae. The 5' end of the message contains a trans-spliced leader SL1. An 18-kb intron is located upstream of the predicted translational start site of the gene, and DNA breakpoints of four gamma-ray-induced alleles were located within this intron. We determined the sequence of a cDNA corresponding to the unc-7 message. The message may encode a 60-kd protein whose amino acid sequence is unrelated to any other available protein sequence; a transmembrane location for the unc-7 protein is predicted. We predict from our analysis of unc-7 genetic mosaics that the unc-7 gene product is not required in muscle cells for wild-type coordination but is probably required in motor neurons (although a hypodermal role has not been excluded). We speculate that unc-7 may be involved in the function of neuronal ion channels.

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Identification Of A Novel Gene Altered In The RQ1 Mutant Strain Affecting Motor Axon Migration In Caenorhabditis Elegans

10.32920/ryerson.14662620 ◽

2021 ◽

Author(s):

Haider Z. Naqvi

Keyword(s):

Caenorhabditis Elegans ◽

Axon Guidance ◽

Motor Neurons ◽

Genetic Background ◽

Germ Line ◽

Strong Indication ◽

Wild Type ◽

C Elegans ◽

Novel Gene ◽

Mutation Region

Novel genetic enhancer screens were conducted targeting mutants involved in the guidance of axons of the DA and DB classes of motor neurons in C. elegans. These mutations are expected in genes that function in parallel to the unc-g/Netrin pathway. The screen was conducted in an unc-5(e53) genetic background and enhancers of the axon guidance defects caused by the absence of UNC-5 were identified. Three mutants were previously identified in the screen called rq1, rq2 and rq3 and two additional mutants called H2-4 and M1-3, were isolated in this study. In order to identify the gene affected by the rq1 mutation, wild-type copies of genes in the mapped rq1 mutation region were injected into the mutants to rescue the phenotypic defects. This is a strong indication that the gene of interest is a novel gene called H04D03.1. Promising results indicate that the H04D03.1 protein also works in germ-line apoptosis.

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Analysis of the Caenorhabditis elegans axonal guidance and outgrowth gene unc-33.

Genetics ◽

10.1093/genetics/132.3.675 ◽

1992 ◽

Vol 132 (3) ◽

pp. 675-689 ◽

Cited By ~ 9

Author(s):

W Li ◽

R K Herman ◽

J E Shaw

Keyword(s):

Caenorhabditis Elegans ◽

Gamma Ray ◽

Protein A ◽

Genomic Region ◽

Axonal Guidance ◽

Significant Similarity ◽

Spliced Leader ◽

Neuronal Processes ◽

Type Size ◽

Intermediate Size

Abstract Mutations in the unc-33 gene of the nematode Caenorhabditis elegans lead to severely uncoordinated movement, abnormalities in the guidance and outgrowth of the axons of many neurons, and a superabundance of microtubules in neuronal processes. We have cloned unc-33 by tagging the gene with the transposable element Tc4. Three unc-33 messages, which are transcribed from a genomic region of at least 10 kb, were identified and characterized. The three messages have common 3' ends and identical reading frames. The largest (3.8-kb) message consists of the 22-nucleotide trans-spliced leader SL1 and 10 exons (I-X); the intermediate-size (3.3-kb) message begins with SL1 spliced to the 5' end of exon V and includes exons V-X; and the smallest (2.8-kb) message begins within exon VII and also includes exons VIII-X. A gamma-ray-induced deletion mutation situated within exon VIII reduces the sizes of all three messages by 0.5 kb. The three putative polypeptides encoded by the three messages overlap in C-terminal sequence but differ by the positions at which their N termini begin; none has significant similarity to any other known protein. A Tc4 insertion in exon VII leads to alterations in splicing that result in three approximately wild-type-size messages: the Tc4 sequence and 28 additional nucleotides are spliced out of the two larger messages; the Tc4 sequence is trans-spliced off the smallest message such that SL1 is added 13 nucleotides upstream of the normal 5' end of the smallest message.

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Identification Of A Novel Gene Altered In The RQ1 Mutant Strain Affecting Motor Axon Migration In Caenorhabditis Elegans

10.32920/ryerson.14662620.v1 ◽

2021 ◽

Author(s):

Haider Z. Naqvi

Keyword(s):

Caenorhabditis Elegans ◽

Axon Guidance ◽

Motor Neurons ◽

Genetic Background ◽

Germ Line ◽

Strong Indication ◽

Wild Type ◽

C Elegans ◽

Novel Gene ◽

Mutation Region

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The C. elegans gene pag-3 is homologous to the zinc finger proto-oncogene gfi-1

Development ◽

10.1242/dev.124.10.2063 ◽

1997 ◽

Vol 124 (10) ◽

pp. 2063-2073 ◽

Cited By ~ 1

Author(s):

Y. Jia ◽

G. Xie ◽

J.B. McDermott ◽

E. Aamodt

Keyword(s):

Gene Expression ◽

Zinc Finger ◽

Motor Neurons ◽

Nonsense Mutation ◽

Zinc Finger Protein ◽

Protein Sequencing ◽

Null Alleles ◽

Northern Analysis ◽

Wild Type ◽

Sister Cells

Mutations in the Caenorhabditis elegans gene pag-3 result in misexpression of touch receptor-specific genes in the BDU interneurons and in motility defects. We cloned pag-3 and found that the gene encodes a C2H2-type zinc finger protein related to the mammalian GFI-1 protein. Sequencing of the three pag-3 alleles showed that two apparent null alleles encode a nonsense mutation before the zinc fingers and a missense mutation in the fourth zinc finger that changes a coordinating histidine to a tyrosine. The third allele contains a nonsense mutation in the N-terminal region but is not a null allele. Northern analysis showed that a single pag-3 transcript of about 1.6 kb is present in embryos and L1, L2 and L3 larvae. pag-3 message levels were about twofold higher in pag-3 mutants than in wild-type animals, which suggested that pag-3 may negatively regulate its own expression. pag-3lacZ fusion genes were expressed in the BDU interneurons, the touch neurons, 11 VA and 11 VB ventral cord motor neurons, two AVF interneurons and in unidentified neurons of the retrovesicular ganglion. The BDU neurons and the ALM touch neurons are lineal sister cells in the AB.a lineage and the VA and VB motor neurons are lineal sister cells in the AB.p lineage. The VA motor neurons are required for backward movement and the VB motor neurons are required for forward movement. Mosaic analysis showed that the wild-type pag-3 gene is required in the AB.p lineage for coordinated movement and in the AB.a lineage to suppress touch neuron gene expression in the BDU neurons. Because pag-3 is expressed in both the BDU neurons and in the touch neurons, another protein(s) not expressed in the touch neurons may interact with pag-3 to repress touch neuron gene expression in the BDU neurons. Alternatively, another protein in the touch receptor cells may inactivate PAG-3 and allow expression of the touch receptor program. These results show that pag-3 is a temporally regulated gene that is expressed early in development and functions in multiple types of neurons. They also strongly suggest that the PAG3 protein is a DNA-binding protein with properties similar to the mammalian proto-oncogene product GFI-1.

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Expression of the unc-4 homeoprotein in Caenorhabditis elegans motor neurons specifies presynaptic input

Development ◽

10.1242/dev.121.9.2877 ◽

1995 ◽

Vol 121 (9) ◽

pp. 2877-2886 ◽

Cited By ~ 10

Author(s):

D.M. Miller ◽

C.J. Niemeyer

Keyword(s):

Caenorhabditis Elegans ◽

Motor Neurons ◽

Ventral Nerve Cord ◽

Chimeric Protein ◽

Precursor Cell ◽

Wild Type ◽

Nematode Caenorhabditis Elegans ◽

Common Precursor ◽

Post Synaptic Neuron ◽

Beta Galactosidase

In the nematode, Caenorhabditis elegans, VA and VB motor neurons arise from a common precursor cell but adopt different morphologies and synapse with separate sets of interneurons in the ventral nerve cord. A mutation that inactivates the unc-4 homeodomain gene causes VA motor neurons to assume the VB pattern of synaptic input while retaining normal axonal polarity and output; the disconnection of VA motor neurons from their usual presynaptic partners blocks backward locomotion. We show that expression of a functional unc-4-beta-galactosidase chimeric protein in VA motor neurons restores wild-type movement to an unc-4 mutant. We propose that unc-4 controls a differentiated characteristic of the VA motor neurons that distinguishes them from their VB sisters, thus dictating recognition by the appropriate interneurons. Our results show that synaptic choice can be controlled at the level of transcription in the post-synaptic neuron and identify a homeoprotein that defines a subset of cell-specific traits required for this choice.

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Mutant Caenorhabditis elegans RNA polymerase II with a 20,000-fold reduced sensitivity to alpha-amanitin.

Genetics ◽

10.1093/genetics/126.4.889 ◽

1990 ◽

Vol 126 (4) ◽

pp. 889-898

Author(s):

T M Rogalski ◽

M Golomb ◽

D L Riddle

Keyword(s):

Caenorhabditis Elegans ◽

Rna Polymerase ◽

Rna Polymerase Ii ◽

Temperature Sensitive ◽

Wild Type ◽

Cell Nuclei ◽

Spliced Leader ◽

Triton X ◽

Alpha Amanitin

Abstract A doubly mutant ama-1(m118m526) gene results in an RNA polymerase (Rpo) II that is unusually resistant to alpha-amanitin. Rpo II activity in isolated Caenorhabditis elegans cell nuclei is inhibited 50% by alpha-amanitin at a concentration of 150 micrograms/ml, making this enzyme 150 times more resistant to the toxin than Rpo II from the singly mutant allele, ama-1(m118), 20,000 times more resistant than the wild-type Rpo II, and about six times more resistant to amanitin than is Rpo III. It was determined that the SL1 spliced leader precursor is transcribed by Rpo II, and this transcript was used to measure Rpo II activity. The Rpo II activity is unstable in vitro, and the mutant strain has a temperature-sensitive sterile phenotype. The highly resistant double mutant was selected among four million progeny of the mutagenized ama-1(m118) parent by its ability to grow and reproduce in 200 micrograms/ml amanitin in the presence of a permeabilizing agent, Triton X-100.

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RegG, a CcpA Homolog, Participates in Regulation of Amylase-Binding Protein A Gene (abpA) Expression inStreptococcus gordonii

Journal of Bacteriology ◽

10.1128/jb.183.11.3521-3525.2001 ◽

2001 ◽

Vol 183 (11) ◽

pp. 3521-3525 ◽

Cited By ~ 16

Author(s):

Jeffrey D. Rogers ◽

Frank A. Scannapieco

Keyword(s):

Catabolite Repression ◽

Binding Protein ◽

Protein A ◽

Brain Heart Infusion ◽

Wild Type ◽

Translational Start Site ◽

Catabolite Control Protein A ◽

Responsive Element ◽

Translational Start ◽

Control Protein

ABSTRACT The amylase-binding protein A (AbpA) of Streptococcus gordonii was found to be undetectable in supernatants of mid-log-phase cultures containing >1% glucose but abundant in supernatants of cultures made with brain heart infusion (BHI), which contains 0.2% glucose. A 10-fold decrease in the level ofabpA mRNA in S. gordonii cells cultured in BHI was noted after the addition of glucose to 1%. Analysis of theabpA sequence revealed a potential catabolite responsive element CRE 153 bp downstream of the putative translational start site. A catabolite control protein A gene (ccpA) homolog fromS. gordonii, designated regG, was cloned. AregG mutant strain demonstrated moderately less repression of abpA transcription in the presence of 1% glucose. Diauxic growth with glucose and lactose was not affected in the RegG mutant compared to the wild-type parental strain. These results suggest that while RegG plays a role in abpA expression, other mechanisms of catabolite repression are present.

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The Effect of Mianserin on Lifespan of Caenorhabditis elegans is Abolished by Glucose

Current Aging Science ◽

10.2174/1874609813999210104203614 ◽

2021 ◽

Vol 13 ◽

Author(s):

Abdullah Almotayri ◽

Jency Thomas ◽

Mihiri Munasinghe ◽

Markandeya Jois

Keyword(s):

Caenorhabditis Elegans ◽

Scaffolding Protein ◽

Lifespan Extension ◽

Wild Type ◽

E Coli ◽

C Elegans ◽

Risk Of Death ◽

Increased Risk ◽

Antidepressant Use ◽

Extension Effect

Background: The antidepressant mianserin has been shown to extend the lifespan of Caenorhabditis elegans (C. elegans), a well-established model organism used in aging research. The extension of lifespan in C. elegans was shown to be dependent on increased expression of the scaffolding protein (ANK3/unc-44). In contrast, antidepressant use in humans is associated with an increased risk of death. The C. elegans in the laboratory are fed Escherichia coli (E. coli), a diet high in protein and low in carbohydrate, whereas a typical human diet is high in carbohydrates. We hypothesized that dietary carbohydrates might mitigate the lifespan-extension effect of mianserin. Objective: To investigate the effect of glucose added to the diet of C. elegans on the lifespan-extension effect of mianserin. Methods: Wild-type Bristol N2 and ANK3/unc-44 inactivating mutants were cultured on agar plates containing nematode growth medium and fed E. coli. Treatment groups included (C) control, (M50) 50 μM mianserin, (G) 73 mM glucose, and (M50G) 50 μM mianserin and 73 mM glucose. Lifespan was determined by monitoring the worms until they died. Statistical analysis was performed using the Kaplan-Meier version of the log-rank test. Results: Mianserin treatment resulted in a 12% increase in lifespan (P<0.05) of wild-type Bristol N2 worms but reduced lifespan by 6% in ANK3/unc-44 mutants, consistent with previous research. The addition of glucose to the diet reduced the lifespan of both strains of worms and abolished the lifespan-extension by mianserin. Conclusion: The addition of glucose to the diet of C. elegans abolishes the lifespan-extension effects of mianserin.

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Sperm Competition in the Absence of Fertilization in Caenorhabditis elegans

Genetics ◽

10.1093/genetics/152.1.201 ◽

1999 ◽

Vol 152 (1) ◽

pp. 201-208 ◽

Cited By ~ 2

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.

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Streblus asper Lour. exerts MAPK and SKN-1 mediated anti-aging, anti-photoaging activities and imparts neuroprotection by ameliorating Aβ in Caenorhabditis elegans

Nutrition and Healthy Aging ◽

10.3233/nha-210121 ◽

2021 ◽

pp. 1-17

Author(s):

Mani Iyer Prasanth ◽

James Michael Brimson ◽

Dicson Sheeja Malar ◽

Anchalee Prasansuklab ◽

Tewin Tencomnao

Keyword(s):

Oxidative Stress ◽

Caenorhabditis Elegans ◽

Stress Resistance ◽

Vital Role ◽

Transgenic Strain ◽

Wild Type ◽

Neuroprotective Effects ◽

C Elegans ◽

Streblus Asper

BACKGROUND: Streblus asper Lour., has been reported to have anti-aging and neuroprotective efficacies in vitro. OBJECTIVE: To analyze the anti-aging, anti-photoaging and neuroprotective efficacies of S. asper in Caenorhabditis elegans. METHODS: C. elegans (wild type and gene specific mutants) were treated with S. asper extract and analyzed for lifespan and other health benefits through physiological assays, fluorescence microscopy, qPCR and Western blot. RESULTS: The plant extract was found to increase the lifespan, reduce the accumulation of lipofuscin and modulate the expression of candidate genes. It could extend the lifespan of both daf-16 and daf-2 mutants whereas the pmk-1 mutant showed no effect. The activation of skn-1 was observed in skn-1::GFP transgenic strain and in qPCR expression. Further, the extract can extend the lifespan of UV-A exposed nematodes along with reducing ROS levels. Additionally, the extract also extends lifespan and reduces paralysis in Aβ transgenic strain, apart from reducing Aβ expression. CONCLUSIONS: S. asper was able to extend the lifespan and healthspan of C. elegans which was independent of DAF-16 pathway but dependent on SKN-1 and MAPK which could play a vital role in eliciting the anti-aging, anti-photoaging and neuroprotective effects, as the extract could impart oxidative stress resistance and neuroprotection.

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