scholarly journals Alterations in the Conserved SL1trans-Spliced Leader of Caenorhabditis elegansDemonstrate Flexibility in Length and Sequence Requirements In Vivo

1999 ◽  
Vol 19 (3) ◽  
pp. 1892-1900 ◽  
Author(s):  
Kimberly C. Ferguson ◽  
Joel H. Rothman
Keyword(s):  
Dna Sequences ◽  
Expression System ◽  
Leader Sequence ◽  
Critical Parameters ◽  
Spliced Leader ◽  
C Elegans ◽  
The One ◽  
High Degree ◽  
Sequence Requirements

ABSTRACT Approximately 70% of mRNAs in Caenorhabditis elegansare trans spliced to conserved 21- to 23-nucleotide leader RNAs. While the function of SL1, the major C. elegans trans-spliced leader, is unknown, SL1 RNA, which contains this leader, is essential for embryogenesis. Efforts to characterize in vivo requirements of the SL1 leader sequence have been severely constrained by the essential role of the corresponding DNA sequences in SL1 RNA transcription. We devised a heterologous expression system that circumvents this problem, making it possible to probe the length and sequence requirements of the SL1 leader without interfering with its transcription. We report that expression of SL1 from a U2 snRNA promoter rescues mutants lacking the SL1-encoding genes and that the essential embryonic function of SL1 is retained when approximately one-third of the leader sequence and/or the length of the leader is significantly altered. In contrast, although all mutant SL1 RNAs were well expressed, more severe alterations eliminate this essential embryonic function. The one non-rescuing mutant leader tested was never detected on messages, demonstrating that part of the leader sequence is essential for trans splicing in vivo. Thus, in spite of the high degree of SL1 sequence conservation, its length, primary sequence, and composition are not critical parameters of its essential embryonic function. However, particular nucleotides in the leader are essential for the in vivo function of the SL1 RNA, perhaps for its assembly into a functional snRNP or for the trans-splicing reaction.

Effect of small flow reversals on aerosol mixing in the alveolar region of the human lung

2004 ◽  
Vol 97 (6) ◽  
pp. 2083-2089 ◽  
Author(s):  
Chantal Darquenne ◽  
G. Kim Prisk
Keyword(s):  
Human Lung ◽  
Sudden Increase ◽  
Residual Volume ◽  
Research Aircraft ◽  
Residual Capacity ◽  
Small Flow ◽  
The One ◽  
High Degree ◽  
Flow Reversals

It has been suggested that irreversibility of alveolar flow combined with a stretched and folded pattern of streamlines can lead to a sudden increase in mixing in the lung. To determine whether this phenomenon is operative in the human lung in vivo, we performed a series of bolus studies with a protocol designed to induce complex folding patterns. Boli of 0.5- and 1-μm-diameter particles were inhaled at penetration volumes (Vp) of 300 and 1,200 ml in eight subjects during short periods of microgravity aboard the National Aeronautics and Space Administration Microgravity Research Aircraft. Inspiration was from residual volume to 1 liter above 1 G functional residual capacity. This was followed by a 10-s breathhold, during which up to seven 100-ml flow reversals (FR) were imposed at Vp = 300 ml and up to four 500-ml FR at Vp = 1,200 ml, and by an expiration to residual volume. Bolus dispersion and deposition were calculated from aerosol concentration and flow rate continuously monitored at the mouth. There was no significant increase in dispersion and deposition with increasing FR except for dispersion between 0 and 7 FR at Vp = 300 ml with 0.5-μm-diameter particles, and this increase was small. This suggested that either the phenomenon of stretch and fold did not occur within the number of FR we performed or that it had already occurred during the one breathing cycle included in the basic maneuver. We speculate that the phenomenon occurred during the basic maneuver, which is consistent with the high degree of dispersion and deposition observed previously in microgravity.

scholarly journals A trans-spliced leader sequence on actin mRNA in C. elegans

Cell ◽  
1987 ◽  
Vol 49 (6) ◽  
pp. 753-761 ◽  
Author(s):  
Michael Krause ◽  
David Hirsh
Keyword(s):  
Leader Sequence ◽  
Spliced Leader ◽  
C Elegans ◽  
Actin Mrna

Similarity of DNA binding and transcriptional regulation by Caenorhabditis elegans MAB-3 and Drosophila melanogaster DSX suggests conservation of sex determining mechanisms

Development ◽  
1999 ◽  
Vol 126 (5) ◽  
pp. 873-881 ◽  
Author(s):  
W. Yi ◽  
D. Zarkower
Keyword(s):  
Dna Binding ◽  
Sex Determination ◽  
Dna Sequences ◽  
Sexual Development ◽  
Yolk Protein ◽  
Binding Motif ◽  
C Elegans ◽  
A Site

Although most animals occur in two sexes, the molecular pathways they employ to control sexual development vary considerably. The only known molecular similarity between phyla in sex determination is between two genes, mab-3 from C. elegans, and doublesex (dsx) from Drosophila. Both genes contain a DNA binding motif called a DM domain and they regulate similar aspects of sexual development, including yolk protein synthesis and peripheral nervous system differentiation. Here we show that MAB-3, like the DSX proteins, is a direct regulator of yolk protein gene transcription. We show that despite containing different numbers of DM domains MAB-3 and DSX bind to similar DNA sequences. mab-3 mutations deregulate vitellogenin synthesis at the level of transcription, resulting in expression in both sexes, and the vitellogenin genes have potential MAB-3 binding sites upstream of their transcriptional start sites. MAB-3 binds to a site in the vit-2 promoter in vitro, and this site is required in vivo to prevent transcription of a vit-2 reporter construct in males, suggesting that MAB-3 is a direct repressor of vitellogenin transcription. This is the first direct link between the sex determination regulatory pathway and sex-specific structural genes in C. elegans, and it suggests that nematodes and insects use at least some of the same mechanisms to control sexual development.

scholarly journals The Bacillus thuringiensis cyt Genes for Hemolytic Endotoxins Constitute a Gene Family

2001 ◽  
Vol 67 (3) ◽  
pp. 1090-1096 ◽  
Author(s):  
Alejandra Guerchicoff ◽  
Armelle Delécluse ◽  
Clara P. Rubinstein
Keyword(s):  
Bacillus Thuringiensis ◽  
Gene Family ◽  
Dna Sequences ◽  
Biologically Active ◽  
Sequence Alignments ◽  
Structural Domains ◽  
Toxic Activity ◽  
Pcr Screening ◽  
High Degree

ABSTRACT In the same way that cry genes, coding for larvicidal delta endotoxins, constitute a large and diverse gene family, thecyt genes for hemolytic toxins seem to compose another set of highly related genes in Bacillus thuringiensis. Although the occurrence of Cyt hemolytic factors in B. thuringiensishas been typically associated with mosquitocidal strains, we have recently shown that cyt genes are also present in strains with different pathotypes; this is the case for themorrisoni subspecies, which includes strains biologically active against dipteran, lepidopteran, and coleopteran larvae. In addition, while one Cyt type of protein has been described in all of the mosquitocidal strains studied so far, the present study confirms that at least two Cyt toxins coexist in the more toxic antidipteran strains, such as B. thuringiensis subsp.israelensis and subsp. morrisoni PG14, and that this could also be the case for many others. In fact, PCR screening and Western blot analysis of 50 B. thuringiensis strains revealed that cyt2-related genes are present in all strains with known antidipteran activity, as well as in some others with different or unknown host ranges. Partial DNA sequences for several of these genes were determined, and protein sequence alignments revealed a high degree of conservation of the structural domains. These findings point to an important biological role for Cyt toxins in the final in vivo toxic activity of many B. thuringiensis strains.

Regulatory myosin light-chain genes of Caenorhabditis elegans

1988 ◽  
Vol 8 (12) ◽  
pp. 5339-5349
Author(s):  
C Cummins ◽  
P Anderson
Keyword(s):  
Caenorhabditis Elegans ◽  
Light Chain ◽  
Calcium Binding ◽  
Myosin Light Chain ◽  
Genomic Region ◽  
Leader Sequence ◽  
Light Chains ◽  
Spliced Leader ◽  
C Elegans ◽  
Regulatory Myosin Light Chain

We have cloned and analyzed the Caenorhabditis elegans regulatory myosin light-chain genes. C. elegans contains two such genes, which we have designated mlc-1 and mlc-2. The two genes are separated by 2.6 kilobases and are divergently transcribed. We determined the complete nucleotide sequences of both mlc-1 and mlc-2. A single, conservative amino acid substitution distinguishes the sequences of the two proteins. The C. elegans proteins are strongly homologous to regulatory myosin light chains of Drosophila melanogaster and vertebrates and weakly homologous to a superfamily of eucaryotic calcium-binding proteins. Both mlc-1 and mlc-2 encode abundant mRNAs. We mapped the 5' termini of these transcripts by using primer extension sequencing of mRNA templates. mlc-1 mRNAs initiate within conserved hexanucleotides at two different positions, located at -28 and -38 relative to the start of translation. The 5' terminus of mlc-2 mRNA is not encoded in the 4.8-kilobase genomic region upstream of mlc-2. Rather, mlc-2 mRNA contains at its 5' end a short, untranslated leader sequence that is identical to the trans-spliced leader sequence of three C. elegans actin genes.

scholarly journals Glycolic acid protects neurons against ischemia in vitro and in two animal models of stroke

2020 ◽  
Author(s):  
Alexandra Chovsepian ◽  
Daniel Berchtold ◽  
Katarzyna Winek ◽  
Uta Mamrak ◽  
Inés Ramírez Álvarez ◽  
...  
Keyword(s):  
Glycolic Acid ◽  
Neuronal Damage ◽  
Ischemia Reperfusion ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Global Cerebral Ischemia ◽  
C Elegans ◽  
The One

ABSTRACTStroke is the second leading cause of death and disability worldwide. Current treatments, like pharmacological thrombolysis or mechanical thrombectomy, re-open occluded arteries but do not protect against ischemia-induced damage caused before reperfusion or ischemia/reperfusion-induced neuronal damage. It has been shown that knocking out djr-1.1 and djr-1.2 or glod-4 results in a decreased tolerance to anhydrobiosis in C elegans dauer larva and that Glycolic Acid (GA) can rescue this phenotype. During the process of desiccation/rehydration, a metabolic stop/start similar to the one observed during ischemia/reperfusion occurs. In this study we tested the protective effect of GA against ischemia in three different models (oxygen-glucose deprivation in vitro and Global cerebral ischemia as well as Middle Cerebral Artery Occlusion in vivo). Our results show that GA, given during reperfusion, strongly protects against ischemia-induced neuronal death, reduces the mortality in mice with large infarcts, significantly reduces the ischemic area in the brain and improves the functional outcome. The effect of GA is stronger when the substance is applied near the damaged tissue (i.e. directly to the neurons in vitro or intra-arterially via the internal carotid artery in vivo). These results suggest that GA treatment has the potential to dramatically reduce the mortality and disability caused by stroke in patients.

scholarly journals Discovery of a Cholecystokinin-Gastrin-Like Signaling System in Nematodes

Endocrinology ◽  
2008 ◽  
Vol 149 (6) ◽  
pp. 2826-2839 ◽  
Author(s):  
Tom Janssen ◽  
Ellen Meelkop ◽  
Marleen Lindemans ◽  
Karen Verstraelen ◽  
Steven J. Husson ◽  
...  
Keyword(s):  
Energy Homeostasis ◽  
Biological Activities ◽  
Digestive Enzyme ◽  
Structural Similarity ◽  
Signaling System ◽  
High Identity ◽  
Cck Receptors ◽  
C Elegans ◽  
High Degree

Members of the cholecystokinin (CCK)/gastrin family of peptides, including the arthropod sulfakinins, and their cognate receptors, play an important role in the regulation of feeding behavior and energy homeostasis. Despite many efforts after the discovery of CCK/gastrin immunoreactivity in nematodes 23 yr ago, the identity of these nematode CCK/gastrin-related peptides has remained a mystery ever since. The Caenorhabditis elegans genome contains two genes with high identity to the mammalian CCK receptors and their invertebrate counterparts, the sulfakinin receptors. By using the potential C. elegans CCK receptors as a fishing hook, we have isolated and identified two CCK-like neuropeptides encoded by neuropeptide-like protein-12 (nlp-12) as the endogenous ligands of these receptors. The neuropeptide-like protein-12 peptides have a very limited neuronal expression pattern, seem to occur in vivo in the unsulfated form, and react specifically with a human CCK-8 antibody. Both receptors and ligands share a high degree of structural similarity with their vertebrate and arthropod counterparts, and also display similar biological activities with respect to digestive enzyme secretion and fat storage. Our data indicate that the gastrin-CCK signaling system was already well established before the divergence of protostomes and deuterostomes.

scholarly journals Regulatory myosin light-chain genes of Caenorhabditis elegans.

1988 ◽  
Vol 8 (12) ◽  
pp. 5339-5349 ◽  
Author(s):  
C Cummins ◽  
P Anderson
Keyword(s):  
Caenorhabditis Elegans ◽  
Light Chain ◽  
Calcium Binding ◽  
Myosin Light Chain ◽  
Genomic Region ◽  
Leader Sequence ◽  
Light Chains ◽  
Spliced Leader ◽  
C Elegans ◽  
Regulatory Myosin Light Chain

We have cloned and analyzed the Caenorhabditis elegans regulatory myosin light-chain genes. C. elegans contains two such genes, which we have designated mlc-1 and mlc-2. The two genes are separated by 2.6 kilobases and are divergently transcribed. We determined the complete nucleotide sequences of both mlc-1 and mlc-2. A single, conservative amino acid substitution distinguishes the sequences of the two proteins. The C. elegans proteins are strongly homologous to regulatory myosin light chains of Drosophila melanogaster and vertebrates and weakly homologous to a superfamily of eucaryotic calcium-binding proteins. Both mlc-1 and mlc-2 encode abundant mRNAs. We mapped the 5' termini of these transcripts by using primer extension sequencing of mRNA templates. mlc-1 mRNAs initiate within conserved hexanucleotides at two different positions, located at -28 and -38 relative to the start of translation. The 5' terminus of mlc-2 mRNA is not encoded in the 4.8-kilobase genomic region upstream of mlc-2. Rather, mlc-2 mRNA contains at its 5' end a short, untranslated leader sequence that is identical to the trans-spliced leader sequence of three C. elegans actin genes.

Cloning and functional characterization of a folate transporter from the nematodeCaenorhabditis elegans

2007 ◽  
Vol 293 (2) ◽  
pp. C670-C681 ◽  
Author(s):  
Krishnaswamy Balamurugan ◽  
Balasubramaniem Ashokkumar ◽  
Mustapha Moussaif ◽  
Ji Ying Sze ◽  
Hamid M. Said
Keyword(s):  
Ph Dependence ◽  
Expression System ◽  
Functional Characterization ◽  
Regulatory Region ◽  
Similar Degree ◽  
Uptake System ◽  
C Elegans ◽  
Uptake Process

Two putative orthologs to the human reduced folate carrier (hRFC), folt-1 and folt-2, which share a 40 and 31% identity, respectively, with the hRFC sequence, have been identified in the Caenorhabditis elegans genome. Functional characterization of the open reading frame of the putative folt-1 and folt-2 showed folt-1 to be a specific folate transporter. Transport of folate by folt-1 expressed in a heterologous expression system showed an acidic pH dependence, saturability (apparent Kmof 1.23 ± 0.18 μM), a similar degree of inhibition by reduced and substituted folate derivatives, sensitivity to the anti-inflammatory drug sulfasalazine (apparent Kiof 0.13 mM), and inhibition by anion transport inhibitors, e.g., DIDS. Knocking down (silencing) or knocking out the folt-1 gene led to a significant inhibition of folate uptake by intact living C. elegans. We also cloned the 5′-regulatory region of the folt-1 gene and confirmed promoter activity of the construct in vivo in living C. elegans. With the use of the transcriptional fusion construct (i.e., folt-1::GFP), the expression pattern of folt-1 in different tissues of living animal was found to be highest in the pharynx and intestine. Furthermore, folt-1::GFP expression was developmentally and adaptively regulated in vivo. These studies demonstrate for the first time the existence of a specialized folate uptake system in C. elegans that has similar characteristics to the folate uptake process of the human intestine. Thus C. elegans provides a genetically tractable model that can be used to study integrative aspects of the folate uptake process in the context of the whole animal level.

STUDIES IN CONGENITAL GENERALIZED LIPODYSTROPHY

1973 ◽  
Vol 72 (3) ◽  
pp. 495-505 ◽  
Author(s):  
Oddmund Søvik ◽  
Svein Oseid
Keyword(s):  
Biological Activity ◽  
Insulin Response ◽  
Epididymal Adipose Tissue ◽  
Large Individual ◽  
Immunoreactive Insulin ◽  
List Type ◽  
Glucose Load ◽  
Congenital Generalized Lipodystrophy ◽  
The One

ABSTRACT The biological activity of plasma insulin from 4 cases of congenital generalized lipodystrophy has been studied, using rat diaphragm and epididymal adipose tissue in vivo. The results are compared with previous data on plasma immunoreactive insulin obtained in these patients. 2 of the 4 cases exhibited unusually high biological insulin activities during the fasting state as well as after an intravenous (iv) glucose load. In the fat pad assay activities as high as 10 000 μU insulin per ml were observed. During childhood the biological insulin activities were generally high, although there were large individual variations. However, in the one case studied after the age of puberty, the insulin response to a glucose load was negligible. Taken together, the biological and immunological activities observed strongly suggest the presence of pancreatic insulin in these patients. It appears that the circulating insulin has a fully biological activity. The decreasing insulin activities after cessation of growth are in agreement with the appearance of frank diabetes at this time.

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