Take-uchi M et al. (1995) Worm Breeder's Gazette "flr-4 is rescued"

Kawakami M, Take-uchi M, Urasaki M, Katsura I, Ishihara T

[Worm Breeder's Gazette, 1995]

We are interested in the functions and genetic interactions of the flr genes, which are defined by fluoride-resistant mutations. They are grouped into two classes by the phenotypes, i.e., class 1 mutants (flr-1, flr-3, flr-4) show slow growth, small blood size and strong resistance to fluoride ion, whereas class 2 mutants (flr-2, flr-5) show normal growth, normal brood size and weak resistance to fluoride ion. Phenotypes of double mutants between the class 1 and class 2 mutations reveal complex and interesting epistasis: they are almost normal in growth and brood size but strongly resistant to fluoride ion (I.Katsura et al. Genetics 136, 145-154 (1994)). The flr mutations also affect neural functions: K.Iwasaki, D.W.C.Liu and J.H.Thomas reported that the class 1 mutants show short defecation cycle periods (Dec-s) (wm95, p286), while we found that some of the flr mutants are defective in chemotaxis (unpublished results) and most of them show synthetic Dauer-constitutive phenotypes (wm95, p303). To elucidate the molecular mechanism of the functions and interactions of the flr gene products, we cloned flr-1 and flr-3 by transposon tagging. flr-1 encodes a degenerin-like ion channel, whereas flr-3 encodes a protein kinase or a kinase-like molecule belonging to a new family (wm95, p304). Furthermore, we recently found that the cosmid F09B12 rescues the slow- growing and Dec-s phenotypes, if it is injected into the gonad of the flr-4(ut7) mutant. A major part of the cosmid has been sequenced already by the genome project. Since it contains an ORF that shows homology to KSS1 protein kinase, we are now testing if subclones containing this ORF can rescue the flr-4 mutation. We expect the studies on the flr genes will reveal a new signal transduction system that affects growth rate and some neural functions in C. elegans.

Take-uchi M et al. (2000) Japanese Worm Meeting "Analysis of class 2 flr genes, which control the growth rate of class 1 flr mutants."

Ishihara T, Take-uchi M, Katsura I, Oishi A

[Japanese Worm Meeting, 2000]

flr (fluoride resistant) mutations are classfied into two categories, class 1 and class 2. Class 1 mutations( flr-1, flr-3 and flr-4) show many phenotypes, such as strong resistance to fluoride ion, slow growth, short defecation cycle periods, defects in the defecation expulsion step, synthetic abnormality in dauer formation,etc. These genes encode an ion channel of the DEG/ENaC superfamily, a kinase-like molecule, and a novel Ser/Thr protein kinase, respectively, which seem to constitute a regulatatory system in the intestine. Class 2 mutations(flr-2 and flr-5) confer weak resistance to fluoride ion and suppress the slow-growing phenotype and synthetic dauer abnormality (but not the defecation abnormality) of class 1 mutations. To elucidate how the class 1 flr regulatory system controls diverse functions, we cloned one of the class 2 flr genes, which probably act downstream of class 1 genes in the regulately cascade. FLR-2 is a secretory protein belonging to the DAN/Gremlin/ Cerberus family (TGF- antagonists). However, it remains to be studied whether FLR-2 antagonizes a soluble signaling molecule like TGF- or it acts, for instance, by binding to a membrane-bound receptor. Recently, we found that class 2 mutants show weak response to benzaldehyde, and that flr-2 is expressed in a few sensory neurons. We plan to continue the analysis of the class 2 genes to elucidate the molecular mechanisms of growth-rate regulation and neural functions.

Take-uchi M et al. (2005) Mol Biol Cell "FLR-4, a novel serine/threonine protein kinase, regulates defecation rhythm in Caenorhabditis elegans."

Kimura KD, Ishihara T, Take-uchi M, Katsura I, Kobayashi Y

[Mol Biol Cell, 2005]

Monitoring Editor: Susan Strome The defecation behavior of the nematode Caenorhabditis elegans is controlled by a 45-s ultradian rhythm. An essential component of the clock that regulates the rhythm is the inositol trisphosphate receptor in the intestine, but other components remain to be discovered. Here, we show that the flr-4 gene, whose mutants exhibit very short defecation cycle periods, encodes a novel serine/threonine protein kinase with a carboxyl terminal hydrophobic region. The expression of functional flr-4::GFP was detected in the intestine, part of pharyngeal muscles and a pair of neurons, but expression of flr-4 in the intestine was sufficient for the wild-type phenotype. Furthermore, laser killing of the flr-4-expressing neurons did not change the defecation phenotypes of wild-type and flr-4 mutant animals. Temperature-shift experiments with a temperature-sensitive flr-4 mutant suggested that FLR-4 acts in a cell-functional rather than developmental aspect in the regulation of defecation rhythms. The function of FLR-4 was impaired by missense mutations in the kinase domain and near the hydrophobic region, where the latter allele seemed to be a weak antimorph. Thus, a novel protein kinase with a unique structural feature acts in the intestine to increase the length of defecation cycle periods.

Take-uchi M et al. (1997) International C. elegans Meeting "GENES THAT AFFECT A BIOLOGICAL RHYTHM IN C. ELEGANS, flr-1 AND flr-4, ENCODE AN ION CHANNEL AND A PROTEIN KINASE, RESPECTIVELY"

Take-uchi M, Katsura I, Ishihara T

[International C. elegans Meeting, 1997]

The defecation behavior of C. elegans, which consists of three sequential muscle-contractions (pBoc, aBoc and Exp), is repeated at intervals of about 40 seconds. The locus and molecular mechanism of this biological clock are still unknown. Mutants in flr-1, flr-3 and flr-4 genes were originally isolated by fluoride-resistance. They show slow growth rate and frequent defecation behavior with rare Exp steps. The former but not the latter depends on the activities of two other flr genes, flr-2 and flr-5. flr-1 encodes an ion channel that belongs to the degenerin and mammalian epithelial sodium channel (DEG/ ENaC) superfamily. Most members of this superfamily contribute to physical sensations, mechanical or osmotic. Four mutation sites were determined. The flr-1::GFP fusion gene is expressed in all intestinal cells through all developmental stages. flr-4 encodes a novel protein kinase. Two mutation sites were determined. The GFP-tagged FLR-4 protein was localized in the intestinal cell surface through all developmental stages, in the cell body and axons of AUA neurons in post-embryonic stages, and in the excretory canal in larval stages. Interestingly, on plain agar plates with bacteria, flr-1(ut11) shows longer defecation intervals with rare Exp steps, and flr-4(ut7) shows longer defecation intervals with clear Exp steps. It may suggest that flr-1 and flr-4 have osmoregulatory defects and that osmotic environments contribute to the defecation frequencies of those mutants.

Take-uchi M et al. (1993) International C. elegans Meeting "Receptor tyrosine kinase kin-8 belongs to a novel subfamily of NSF-R(trk)s with a kringle structure in the extracellular domain."

Ohshima YM, Take-uchi M, Koga M, Tatsuji T

[International C. elegans Meeting, 1993]

Take-uchi M et al. (1998) Proc Natl Acad Sci U S A "An ion channel of the degenerin/epithelial sodium channel superfamily controls the defecation rhythm in Caenorhabditis elegans."

Katsura I, Ishihara T, Kondo K, Kawakami M, Amano T, Take-uchi M

[Proc Natl Acad Sci U S A, 1998]

Ultradian rhythms are widespread phenomena found in various biological organisms. A typical example is the defecation behavior of the nematode Caenorhabditis elegans, which repeats at about 45-sec intervals. To elucidate the mechanism, we studied flr-1 mutants, which show very short defecation cycle periods. The mutations also affect some food-related functions, including growth rate, the expulsion step of defecation behavior, and the regulation of the dauer larva (a nonfeeding, special third-stage larva) formation in the unc-3 (Olf-1/EBF homolog) background. The flr-1 gene encodes a novel ion channel belonging to the DEG/ENaC (C. elegans degenerin and mammalian epithelial sodium channel) superfamily. A flr-1::GFP (green fluorescent protein) fusion gene that can rescue the flr-1 mutant phenotypes is expressed only in the intestine from embryos to adults. These results suggest that FLR-1 may be a component of an intestinal regulatory system that controls the defecation rhythm as well as other functions.

Peixoto H et al. (2019) Molecules "Bark Extract of the Amazonian Tree Endopleura uchi (Humiriaceae) Extends Lifespan and Enhances Stress Resistance in Caenorhabditis elegans."

Wang X, Silva E, Braun M, Peixoto H, Roxo M, Valente K, Wink M

[Molecules, 2019]

<i>Endopleura uchi</i> (Huber) Cuatrec (Humiriaceae), known as uxi or uxi-amarelo in Brazil, is an endemic tree of the Amazon forest. In traditional medicine, its stem bark is used to treat a variety of health disorders, including cancer, diabetes, arthritis, uterine inflammation, and gynecological infections. According to HPLC analysis, the main constituent of the bark extract is the polyphenol bergenin. In the current study, we demonstrate by in vitro and in vivo experiments the antioxidant potential of a water extract from the stem bark of <i>E. uchi</i>. When tested in the model organism <i>Caenorhabditis elegans,</i> the extract enhanced stress resistance via the DAF-16/FOXO pathway. Additionally, the extract promoted an increase in the lifespan of the worms independent from caloric restriction. It also attenuated the age-related muscle function decline and formation of polyQ40 plaques, as a model for Huntington's disease. Thus, these data support anti-aging and anti-oxidant properties of <i>E. uchi</i>, which has not yet been described. More studies are needed to assess the real benefits of <i>E. uchi</i> bark for human health and its toxicological profile.

Koga M et al. (1999) Development "Control of DAF-7 TGF-(alpha) expression and neuronal process development by a receptor tyrosine kinase KIN-8 in Caenorhabditis elegans."

Ohshima YM, Koga M, Take-uchi M, Tameishi T

[Development, 1999]

KIN-8 in C. elegans is highly homologous to human ROR-1 and 2 receptor tyrosine kinases of unknown functions. These kinases belong to a new subfamily related to the Trk subfamily. A kin-8 promoter::gfp fusion gene was expressed in ASI and many other neurons as well as in pharyngeal and head muscles. A kin-8 deletion mutant was isolated and showed constitutive dauer larva formation (Daf-c) phenotype: about half of the F(1) progeny became dauer larvae when they were cultivated on an old lawn of E. coli as food. Among the cells expressing kin-8::gfp, only ASI sensory neurons are known to express DAF-7 TGF-(beta), a key molecule preventing dauer larva formation. In the kin-8 deletion mutant, expression of daf-7::gfp in ASI was greatly reduced, dye-filling in ASI was specifically lost and ASI sensory processes did not completely extend into the amphid pore. The Daf-c phenotype was suppressed by daf-7 cDNA expression or a daf-3 null mutation. ASI-directed expression of kin-8 cDNA under the daf-7 promoter or expression by a heat shock promoter rescued the dye-filling defect, but not the Daf-c phenotype, of the kin-8 mutant. These results show that the kin-8 mutation causes the Daf-c phenotype through reduction of the daf-7 gene expression and that KIN-8 function is cell-autonomous for the dye-filling in ASI. KIN-8 is required for the process development of ASI, and also involved in promotion of daf-7 expression through a physiological or developmental function.

Bignone FA (1999) Theoretical Computer Science "Coupled map lattices dynamics on a variable space for the study of development:: A general discussion on Caenorhabditis elegans."

Bignone FA

[Theoretical Computer Science, 1999]

The implementation of models to simulate dynamical aspects of biological systems, particularly in the study of replication and development, has to take into account that gene-gene interactions and cell-cell interactions take place in a space of variable structure and size. In this paper, we discuss the possibility of a detailed reconstruction olf cellular dynamics during early stages of development with coupled map lattices or formalizations of Lindenmayer grammars.

Raizen D (2020) J Neurogenet "Worms sleep: a perspective."

Raizen D

[J Neurogenet, 2020]

I review the history of sleep research in <i>Caenorhabditis elegans</i>, briefly introduce the four articles in this issue focused on worm sleep and propose future directions our field might take.