Chuang P-T et al. (1996) Science "Sex-specific assembly of a dosage compensation complex on the nematode X chromosome."

Lieb JD, Meyer JB, Chuang P-T

[Science, 1996]

In nematodes, flies, and mammals, dosage compensation equalizes X-chromosome gene expression between the sexes through chromosome-wide regulatory mechanisms that function in one sex to adjust the levels of X-linked transcripts. Here, a dosage compensation complex was identified in the nematode Caenorhabditis elegans that reduces transcript levels from the two X chromosomes in hermaphrodites. This complex contains at least four proteins, including products of the dosage compensation genes dpy-26 and dpy-27. Specific localization of the complex to the hermaphrodite X chromosomes is conferred by XX-specific regulatory genes that coordinately control both sex determination and dosage compensation.AD - Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.FAU - Chuang, P TAU - Chuang PTFAU - Lieb, J DAU - Lieb JDFAU - Meyer, B JAU - Meyer BJLA - engID - GM30702/GM/NIGMSID - T32 GM07127/GM/NIGMSPT - Journal ArticleCY - UNITED STATESTA - ScienceJID - 0404511RN - 0 (Carrier Proteins)RN - 0 (DPY-27 protein)RN - 0 (Helminth Proteins)RN - 0 (Nuclear Proteins)RN - 0 (RNA, Helminth)RN - 0 (RNA, Messenger)SB - IM

Chuang P-T et al. (1994) Cell "DPY-27:a chromosome condensation protein homolog that regulates C. elegans dosage compensation through association with the X chromosome."

Meyer BJ, Chuang P-T, Albertson DG

[Cell, 1994]

dpy-27 is an essential dosage compensation gene that acts to reduce expression of both hermaphrodite X chromosomes. The DPY-27 protein becomes specifically localized to the X chromosome of wild-type XX embryos, but remains diffusely distributed throughout the nuclei of male (XO) embryos. In xol-1 mutant XO embryos that activate the XX mode of dosage compensation and die from inappropriately low X chromosome transcript levels, Dpy-27 becomes localized to X. Therefore, sex specificity of the dosage compensation process is regulated at the step of DPY-27 X chromosome localization. DPY-27 exhibits striking similarity to proteins required for assembly and structural maintenance of Xenopus chromosomes in vitro and for segregation of yeast chromosomes in vivo. These findings suggest a link between global regulation of gene expression and higher order chromosome structure. We propose that Dpy-27 implements dosage compensation by condensing the chromatin structure of X in a manner that causes general reduction of X chromosome expression.

Hsu DR et al. (1995) Development "DPY-30, a nuclear protein essential early in embryogenesis for Caenorhabditis elegans dosage compensation."

Chuang P-T, Meyer BJ, Hsu DR

[Development, 1995]

DPY-30 is an essential component of the C, elegans dosage compensation machinery that reduces X chromosome transcript levels in hermaphrodites (XX). DPY-30 is required for the sex-specific association of DPY-27 (a chromosome condensation protein homolog) with the hermaphrodite X chromosomes, Loss of dpy-30 activity results in XX-specific lethality, We demonstrate that dpy-30 encodes a novel nuclear protein of 123 amino acids that is present in both hermaphrodites and males (XO) throughout development. DPY-30 itself is not associated with the X chromosomes, nor is its pattern of expression perturbed by mutations in the gene hierarchy that controls dosage compensation, Therefore, DPY-30 is a ubiquitous factor that is likely to promote the hermaphrodite-specific association of DPY-27 with X by affecting the activity of a sex-specific dosage compensation gene. In XO animals, DPY-30 is required for developmental processes other than dosage compensation: coordinated movement, normal body size, correct tail morphology and mating behavior. We demonstrate that rescue of both the XX-specific lethality and the XO-specific morphological defects caused by dpy-30 mutations can be achieved by inducing dpy-30 transcripts either in the mother or in the embryo through the end of gastrulation, dpy-30 appears to be cotranscribed in an operon with a

Chen T et al. (2023) Int J Biol Macromol "Antioxidant potential evaluation of polysaccharides from Camellia oleifera Abel in vitro and in vivo."

Ding CB, Liu L, Tang M, Cao XH, Chen T, Yang HY, Huang Y, Zhao XR, Zhou LJ, Feng SL

[Int J Biol Macromol, 2023]

The extraction process, structural characterization and free radical scavenging ability of polysaccharides from Camellia oleifera have already been widely studied. However, the antioxidant activities are still lack of systematic experiments. In this study, we used Hep G2 cells and Caenorhabditis elegans to evaluate the antioxidant potential of polysaccharides that from C. oleifera flowers (P-CF), leaves (P-CL), seed cakes (P-CC) and fruit shells (P-CS). The results showed all these polysaccharides could protect cells from oxidative damage induced by t-BHP. The highest cell viabilities were 66.46 ± 1.36 % (P-CF), 55.2 ± 2.93 % (P-CL), 54.49 ± 1.29 % (P-CC) and 61.45 ± 1.67 % (P-CS), respectively. Studies have shown that four polysaccharides may protect cells from apoptosis by reducing ROS levels and maintaining MMP balance. Moreover, P-CF, P-CL, P-CC and P-CS increased the survival rate of C. elegans under thermal stress, which reduced the production of ROS by 56.1 ± 0.67 %, 59.37 ± 1.79 %, 16.63 ± 2.51 % and 27.55 ± 2.62 %, respectively. P-CF and P-CL showed stronger protective effects on C. elegans by increasing the nuclear entry rate of DAF-16 and stimulating the expression of SOD-3. Our study suggested that C. oleifera polysaccharides have the potential to develop into a natural supplement agent.

Wang DY et al. (2009) Zhonghua Yu Fang Yi Xue Za Zhi "[Aluminium toxicosis causing transferable defects from exposed animals to their progeny in Caenorhabditis elegans]."

Yang YC, Wang Y, Wang DY

[Zhonghua Yu Fang Yi Xue Za Zhi, 2009]

OBJECTIVE: To study the possibly transferable properties of multi-biological toxicities caused by aluminium exposure from exposed animals to their progeny. METHODS: Multi-biological toxicities in aluminium (2.5 micromol/L, 75 micromol/L, and 200 micromol/L) exposed animals and their progeny were analyzed by using model organism Caenorhabditis elegans. Endpoints of lifespan, development, reproduction, locomotion behavior and behavioral plasticity were selected for the assay of multiple toxicities and their transfer properties. Four groups of experiments were performed for each endpoint assay. Twenty animals were used for assay of lifespan, development, reproduction and locomotion behaviors, and 100 animals were used for assay of behavioral plasticity in each group experiment. The data were performed for statistical analysis using SPSS 13.0 software. RESULTS: Our data suggest that the aluminium exposure could result in multi-biological defects of phenotypes and behaviors. As compared to those average survival days, 24 d, body size, (1.30 +/- 0.05) mm; brood size, (278 +/- 20); generation time (64.0 +/- 1.2) h; body bend, (45.8 +/- 3.0) times, head thrash, (109.33 +/- 7.30) times, behavioral plasticity (3 +/- 4)% in 0 micromol/L aluminum exposed animals, the low-concentration (2.5 micromol/L) aluminium exposure caused severe defects of average survival days (20 d), body size [(1.12 +/- 0.02 ) mm, t = 14.55, P<0.01], brood size [(145 +/- 23), t = 30.62, P< 0.01], body bend [(29.8 +/- 3.0), t = 20.31, P<0.01], and head thrash, (95.8 +/- 6.2), t = 16.43, P < 0.01]. High-concentration aluminium exposure could further result in severe defects of generation time [75 micromol/L, (67.0 +/- 1.7 ) h, t = 8.92, P<0.01; 200 micromol/L, (70.7 +/- 1.5) h, t =15.13, P<0.01] and behavioral plasticity [75 micromol/L, (16.5 +/- 3.0)%, t = 27.11, P<0.05; 200 micromol/L, (23.5 +/- 4.0)%, t = 16.43, P<0.01]. Moreover, most of these toxicities caused by high-concentration aluminium exposure could be transferred from exposed animals to their progeny. In progeny animals, the phenotypic and behavioral defects might be only partially (such as body size, brood size, and locomotion behaviors) or very slightly (such as the lifespan defects induced by high concentrations of aluminium exposure) rescued. Especially, the generation time defects induced by aluminium exposure would become more severe in progeny animals than in their parents. CONCLUSION: The multi-biological defects caused by aluminium exposure might be largely transferred from exposed animals to their progeny in Caenorhabditis elegans.

Loo TW et al. (2013) Biochemistry "A salt bridge in intracellular loop 2 is essential for folding of human p-glycoprotein."

Clarke DM, Loo TW

[Biochemistry, 2013]

There is no high-resolution structure of the human P-glycoprotein (P-gp, ABCB1) drug pump. Homology models based on the crystal structures of mouse and Caenorhabditis elegans P-gps show extensive contacts between intracellular loop 2 (ICL2, in the first transmembrane domain) and the second nucleotide-binding domain. Human P-gp modeled on these P-gp structures yields different ICL2 structures. Only the model based on the C. elegans P-gp structure predicts the presence of a salt bridge. We show that the Glu256-Arg276 salt bridge was critical for P-gp folding.

Arduengo PM et al. (1998) J Cell Sci "The presenilin protein family member SPE-4 localizes to an ER/Golgi derived organelle and is required for proper cytoplasmic partitioning during Caenorhabditis elegans spermatogenesis."

L'Hernault SW, Appleberry OK, Chuang P-T, Arduengo PM

[J Cell Sci, 1998]

During Caenorhabditis elegans spermatogenesis, asymmetric partitioning of cellular components principally occurs via ER/Golgi-derived organelles, named fibrous body-membranous organelles. In C. elegans spe-4 mutants, morphogenesis of fibrous body-membranous organelle complexes is defective and spermatogenesis arrests at an unusual cellular stage with four haploid nuclei within a common cytoplasm. The spe-4 encoded integral membrane protein is a diverged member of the presenilin family implicated in early onset Alzheimer's disease. Specific antisera were used to show that SPE-4 resides within the fibrous body-membranous organelles membranes during wild-type spermatogenesis. Several spe-4 recessive mutants were examined for SPE-4 immunoreactivity and a deletion mutant lacks detectable SPE-4 while either of two missense mutants synthesize and localize immunoreactive SPE-4 within their fibrous body-membranous organelles. One of these missense mutations is located within a motif that is common to all presenilins. spe-4 mutants were also examined for other partitioning defects and tubulin was found to accumulate in unusual deposits close to the plasma membrane. These results suggest that wild-type SPE-4 is required for proper localization of macromolecules that are subject to asymmetric partitioning during spermatogenesis.

Lieb JD et al. (1998) Cell "MIX-1: an essential component of the C. elegans mitotic machinery executes X chromosome dosage compensation."

Albrecht MR, Lieb JD, Meyer BJ, Chuang P-T

[Cell, 1998]

We show that a functional component of the C. elegans mitotic machinery regulates X chromosome gene expression. This protein, MIX-1, is a member of the dosage compensation complex that associates specifically with hermaphrodite X chromosomes to reduce their gene expression during interphase. MIX-1 also associates with all mitotic chromosomes to ensure their proper segregation. Both dosage compensation and mitosis are severely disrupted by mix-1 mutations. MIX-1 belongs to the SMC protein family required for mitotic chromosome condensation and segregation in yeast and frogs. Thus, an essential, conserved component of mitotic chromosomes has been recruited to the dosage compensation process. Rather than dosage compensation and mitosis being achieved by two separate sets of related genes, these two processes share an identical component, indicating a common mechanism for establishing higher order chromosome structure and proper X chromosome gene expression.

Sarabhai S et al. (2013) PLoS One "Ellagic acid derivatives from Terminalia chebula Retz. downregulate the expression of quorum sensing genes to attenuate Pseudomonas aeruginosa PAO1 virulence."

Sarabhai S, Sharma P, Capalash N

[PLoS One, 2013]

BACKGROUND: Burgeoning antibiotic resistance in Pseudomonas aeruginosa has necessitated the development of anti pathogenic agents that can quench acylhomoserine lactone (AHL) mediated QS with least risk of resistance. This study explores the anti quorum sensing potential of T. chebula Retz. and identification of probable compounds(s) showing anti QS activity and the mechanism of attenuation of P. aeruginosa PAO1 virulence factors. METHODS AND RESULTS: Methanol extract of T. chebula Retz. fruit showed anti QS activity using Agrobacterium tumefaciens A136. Bioactive fraction (F7), obtained by fractionation of methanol extract using Sephadex LH20, showed significant reduction (p<0.001) in QS regulated production of extracellular virulence factors in P. aeruginosa PAO1. Biofilm formation and alginate were significantly (p<0.05) reduced with enhanced (20%) susceptibility to tobramycin. Real Time PCR of F7 treated P. aeruginosa showed down regulation of autoinducer synthase (lasI and rhlI) and their cognate receptor (lasR and rhlR) genes by 89, 90, 90 and 93%, respectively. Electrospray Ionization Mass Spectrometry also showed 90 and 64% reduction in the production of 3-oxo-C(12)HSL and C(4)HSL after treatment. Decrease in AHLs as one of the mechanisms of quorum quenching by F7 was supported by the reversal of inhibited swarming motility in F7-treated P. aeruginosa PAO1 on addition of C(4)HSL. F7 also showed antagonistic activity against 3-oxo-C(12)HSL-dependent QS in E. coli bioreporter. C. elegans fed on F7-treated P. aeruginosa showed enhanced survival with LT50 increasing from 24 to 72 h. LC-ESI-MS of F7 revealed the presence of ellagic acid derivatives responsible for anti QS activity in T. chebula extract. CONCLUSIONS: This is the first report on anti QS activity of T. chebula fruit linked to EADs which down regulate the expression of lasIR and rhlIR genes with concomitant decrease in AHLs in P. aeruginosa PAO1 causing attenuation of its virulence factors and enhanced sensitivity of its biofilm towards tobramycin.

Samuel ADT et al. (2003) J Neurosci "Synaptic activity of the AFD neuron in Caenorhabditis elegans correlates with thermotactic memory."

Murthy VN, Samuel ADT, Silva RA

[J Neurosci, 2003]

Thermotactic behavior in Caenorhabditis elegans is sensitive to both a worm's ambient temperature (T-amb) and its memory of the temperature of its cultivation (T-cult). The AFD neuron is part of a neural circuit that underlies thermotactic behavior. By monitoring the fluorescence of pH-sensitive green fluorescent protein localized to synaptic vesicles, we measured the rate of the synaptic release of AFD in worms cultivated at temperatures between 15 and 25degreesC, and subjected to fixed, ambient temperatures in the same range. We found that the rate of AFD synaptic release is high if either T-amb > T-cult or T-amb > T-cult, but AFD synaptic release is low if T-amb congruent to T-cult. This suggests that AFD encodes a direct comparison between T-amb and T-cult.