Gao L et al. (2004) J Biol Chem "Isoforms of the polarity protein par6 have distinct functions."

Macara IG, Gao L

[J Biol Chem, 2004]

PAR-6 is essential for asymmetric division of the Caenorhabditis elegans zygote. It is also critical for cell polarization in many other contexts, throughout the Metazoa. The Par6 protein contains a PDZ domain and a partial CRIB (Cdc42/Rac interactive binding) domain, which mediate interactions with other polarity proteins such as Par3, Cdc42, Pals1 and Lgl. A family of mammalian Par6 isoforms (Par6A-D) has been described, but the significance of this diversification has been unclear. Here, we demonstrate that Par6 family members localize differently when expressed in MDCK epithelial cells and have distinct effects on tight junction (TJ) assembly. Par6B localizes to the cytosol and inhibits TJ formation, but Par6A co-localizes predominantly with the TJ marker ZO-1 at cell-cell contacts and does not affect junctions. These functional differences correlate with differences in Pals1 binding - Par6B interacts strongly with Pals1, whereas Par6A binds very weakly to Pals1 even in the presence of active Cdc42. Pals1 has a low affinity for the isolated CRIB+PDZ domain of Par6A, but analysis of chimeras showed that in addition, Pals1 binding is blocked by an inhibitory property of the N-terminus of Par6A. Unexpectedly, the localization of Par6A to cell-cell contacts is Cdc42-independent.

Chikilian ML et al. (1994) J Parasitol "Ultrastructural comparison of extracellular and intracellular encapsulation of Brugia malayi in Anopheles quadrimaculatus."

Chikilian ML, Bradley TJ, Knight JW, Nayar JK

[J Parasitol, 1994]

Ultrastructural aspects of extracellular humoral encapsulation of microfilariae of Brugia malayi in the hemocoel of Anopheles quadrimaculatus were compared with those of intracellular encapsulation of first-stage larvae (L1) of the same parasite species, in the thoracic muscle cells of the same species of mosquito. The results showed that extracellular humoral encapsulation of microfilarial sheaths, and sheathed and exsheathed microfilariae, in the hemocoel of mosquitoes occurs around the parasite within the first 6 hr postingestion, apparently without initial participation of hemocytes. Hemocytes and their remnants were observed near the parasite during the first 6 hr postingestion. Within the next 24 hr, hemocytes attach to the initial humoral capsule. By contrast, intracellular encapsulation of L1S is initiated by the accumulation of a dense cytoplasmic layer derived from the infected thoracic muscle cell. Melanin deposits accumulate in this layer adjacent to the parasite cuticle, again without visible participation of hemocytes.

Kim MR et al. (2022) Phytomedicine "Schisandrin C improves leaky gut conditions in intestinal cell monolayer, organoid, and nematode models by increasing tight junction protein expression."

Cho SY, Kim JY, Kim JH, Nguyen UTT, Cha KH, Choi KY, Kim MR, Kim WK, Ha NM, Kang K, Lee HJ

[Phytomedicine, 2022]

Background: Leaky gut symptoms and inflammatory bowel disease (IBD) are associated with damaged intestinal mucosa, intestinal permeability dysfunction by epithelial cell cytoskeleton contraction, disrupted intercellular tight junction (TJ) protein expression, and abnormal immune responses and are intractable diseases.Purpose: We evaluated the effects of schisandrin C, a dibenzocyclooctadiene lignan from Schisandra chinensis, on intestinal inflammation and permeability dysfunction in gut mimetic systems: cultured intestinal cells, intestinal organoids, and a Caenorhabditis elegans model.Methods: Schisandrin C was selected from 9 lignan compounds from S. chinensis based on its anti-inflammatory effects in HT-29 human intestinal cells. IL-1β and Pseudomonas aeruginosa supernatants were used to disrupt intestinal barrier formation in vitro and in C. elegans, respectively. The effects of schisandrin C on transepithelial electrical resistance (TEER) and intestinal permeability were evaluated in intestinal cell monolayers, and its effect on intestinal permeability dysfunction was tested in mouse intestinal organoids and C. elegans by measuring fluorescein isothiocyanate (FITC)-dextran efflux. The effect of schisandrin C on TJ protein expression was investigated by western blotting and fluorescence microscopy. The signaling pathway underlying these effects was also elucidated.Results: Schisandrin C ameliorated intestinal permeability dysfunction in three IBD model systems and enhanced epithelial barrier formation via upregulation of ZO-1 and occludin in intestinal cell monolayers and intestinal organoids. In Caco-2 cells, schisandrin C restored IL-1β-mediated increases in MLCK and p-MLC expression, in turn blocking cytoskeletal contraction and subsequent intestinal permeabilization. Schisandrin C inhibited NF-ĸB and p38 MAPK signaling, which regulates MLCK expression and structural reorganization of the TJ complex in Caco-2 cells. Schisandrin C significantly improved abnormal FITC-dextran permeabilization in both intestinal organoids and C. elegans.Conclusion: Schisandrin C significantly improves abnormal intestinal permeability and regulates the expression of TJ proteins, long MLCK, p-MLC, and inflammation-related proteins, which are closely related to leaky gut symptoms and IBD development. Therefore, schisandrin C is a candidate to treat leaky gut symptoms and IBDs.

Suzuki A et al. (2002) J Cell Sci "aPKC kinase activity is required for the asymmetric differentiation of the premature junctional complex during epithelial cell polarization."

Shimizu M, Ebnet K, Hashiba K, Ohno S, Ishiyama C, Suzuki A

[J Cell Sci, 2002]

We have previously shown that aPKC interacts with cell polarity proteins PAR-3 and PAR-6 and plays an indispensable role in cell polarization in the C. elegans one-cell embryo as well as in mammalian epithelial cells. Here, to clarify the molecular basis underlying this aPKC function in mammalian epithelial cells, we analyzed the localization of aPKC and PAR-3 during the cell repolarization process accompanied by wound healing of MTD1-A epithelial cells. Immunofluorescence analysis revealed that PAR-3 and aPKClambda translocate to cell-cell contact regions later than the formation of the primordial spot-like adherens junctions (AJs) containing E-cadherin and ZO-1. Comparison with three tight junction (TJ) membrane proteins, JAM, occludin and claudin-1, further indicates that aPKClambda is one of the last TJ components to be recruited. Consistently, the expression of a dominant-negative mutant of aPKClambda (aPKClambdakn) in wound healing cells does not inhibit the formation of the spot-like AJs; rather, it blocks their development into belt-like AJs. These persistent spot-like AJs in aPKClambda-expressing cells contain all TJ membrane proteins and PAR-3, indicating that aPKC kinase activity is not required for their translocation to these premature junctional complexes but is indispensable for their further differentiation into belt-like AJs and TJs. Cortical bundle formation is also blocked at the intermediate step where fine actin bundles emanating from premature cortical bundles link the persistent spot-like AJs at apical tips of columnar cells. These results suggest that aPKC contributes to the establishment of epithelial cell polarity by promoting the transition of fibroblastic junctional structures into epithelia-specific asymmetric ones.

Sengupta P et al. (2014) Traffic "New insights into an old organelle: meeting report on biology of cilia and flagella."

Barr MM, Sengupta P

[Traffic, 2014]

The rising interest of the scientific community in cilia biology was evident from the fact that registration for the third FASEB conference on 'The Biology of Cilia and Flagella' closed out before the early bird deadline. Cilia and flagella are organelles of profound medical importance; defects in their structure or function result in a plethora of human diseases called ciliopathies. 240 clinicians and basic scientists from around the world gathered from 23 June 2013 to 28 June 2013 at Sheraton at the Falls, Niagara Falls, NY to present and discuss their research on this intensely studied subcellular structure. The meeting was organized by Gregory Pazour (University of Massachusetts Medical School), Bradley Yoder (University of Alabama-Birmingham), and Maureen Barr (Rutgers University) and was sponsored by the Federation of American Societies for Experimental Biology (FASEB). Here, we report highlights, points of discussion, and emerging themes from this exciting meeting.

Barbazuk BW et al. (1995) Worm Breeder's Gazette "Correlation of the Genetic and Physical Maps Within the rol-3 Region of LGV (left)."

Baillie DL, Barbazuk BW

[Worm Breeder's Gazette, 1995]

Correlation of the Genetic and Phvsical maps within the rol-3 region of LGV (left) W. Bradley Barbazuk and David L. Baillie Institute of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC. CANADA, VSA 1 S6 In an attempt to identify the physical location of the rol-3 (V) gene we have begun the systematic germ-line transformation rescue of lethal mutations within zones 16-18 of LGV (JOHNSEN and BAILLIE, GENETICS 129: 735-?52). Using H. Kagawa's placement of unc-68 (WBG 12(4)) as a starting point we began to inject cosmids to the right of C46C6 into N2 hermaphrodites. In doing so we were able to obtain a battery of strains each carrying cosmids singly, or multiply, in stable arrays which were then used as mini-duplications in subsequent crosses to lethal bearing strains. In total we used eight cosmid bearing strains and one YAC bearing strain in the rescue of 13 lethal mutations including rol-3 (Table 1). Our germ-line transformation rescue data has enabled us to split up and order some of the lethal mutations within the zone 16-18 gene clusters. (Figure 1). We would like to thank C. Mello and J. Priess for providing a strain carrying an array composed of ZK307, F25G6 and FOlH8, as well as providing purified DNA for many of the cosmids injected.

Curtis C et al. (2007) Genome Biol "Transcriptional profiling of MnSOD-mediated lifespan extension in Drosophila reveals a species-general network of aging and metabolic genes."

Tower J, Badrinath A, Waskar M, Ford D, Levine RL, Folk D, Skvortsov D, Landis GN, Curtis C, Abdueva D, Wehr NB, Bradley TJ, Hoe N, Tavare S, Luu A

[Genome Biol, 2007]

ABSTRACT: BACKGROUND: Several interventions increase lifespan in model organisms, including reduced insulin/IGF-like signaling, FOXO transcription factor activation, dietary restriction, and superoxide dismutase (SOD) over-expression. One question is whether these manipulations function through different mechanisms, or whether they intersect on common processes affecting aging. RESULTS: A doxycycline-regulated system was used to over-express Manganese-SOD (MnSOD) in adult Drosophila, yielding increases in mean and maximal lifespan of 20%. Increased lifespan resulted from lowered initial mortality rate and required MnSOD over-expression in the adult. Transcriptional profiling indicated that the expression of specific genes was altered by MnSOD in a manner opposite to their pattern during normal aging, revealing a set of candidate biomarkers of aging enriched for carbohydrate metabolism genes and suggesting a true delay in physiological aging, rather than a novel phenotype. Strikingly, cross-dataset comparisons indicated that the pattern of gene expression caused by MnSOD was similar to that observed in long-lived C. elegans insulin-like signaling mutants and to the xenobiotic stress response, thus exposing potential conserved longevity promoting genes and implicating detoxification in Drosophila longevity. CONCLUSIONS: The data suggest that MnSOD up-regulation and a retrograde signal of reactive oxygen species from the mitochondria normally function as an intermediate step in the extension of lifespan caused by reduced insulin-like signaling in various species. The results implicate a species-conserved net of coordinated genes that affect the rate of senescence by modulating energetic efficiency, purine biosynthesis, apoptotic pathways, endocrine signals, and the detoxification and excretion of metabolites.

Curtis C et al. (2016) Genome Biol "Erratum to: Transcriptional profiling of MnSOD-mediated lifespan extension in Drosophila reveals a species-general network of aging and metabolic genes."

Landis GN, Luu A, Wehr NB, Curtis C, Ford D, Abdueva D, Hoe N, Levine RL, Waskar M, Skvortsov D, Badrinath A, Bradley TJ, Tavare S, Folk D, Tower J

[Genome Biol, 2016]

Olivia Am Bales et al. (2005) International Worm Meeting "Defining IP3 signals in the C. elegans pharynx."

Olivia Am Bales, Howard A Baylis

[International Worm Meeting, 2005]

Worms show an increased pharyngeal pumping rate on exposure to food, and this increase requires signalling by the second messenger inositol 1,4,5-trisphosphate (IP3) through the IP3 receptor itr-1 1. We are using complementary techniques to identify the signalling components upstream of IP3 production and to observe the spatiotemporal nature of the IP3 signal in the pharynx. Phospholipase C hydrolyses the membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2) to generate IP3, and the C. elegans phospholipase C genes plc-3 and plc-4 are expressed in pharyngeal muscle. RNA interference and analysis of a loss-of-function mutant suggest a role for plc-3 in the upregulation of pharyngeal pumping on food. We are also developing a system for visualising IP3 signals in the pharynxes of intact worms, using a fusion protein of GFP and the pleckstrin homology (PH) domain. Translocation of this protein can be used to follow the production of IP3 2. We are currently investigating the movements of the PH-GFP fusion in wild-type and mutant worms following stimulation by the muscarinic agonist arecoline.1. Walker, D. S., Gower, N. J., Ly, S., Bradley, G. L., and Baylis, H. A. (2002). Regulated disruption of inositol 1,4,5-trisphosphate signaling in Caenorhabditis elegans reveals new functions in feeding and embryogenesis. Mol Biol Cell 13, 1329-1337.2. Varnai, P., and Balla, T. (1998). Visualization of phosphoinositides that bind pleckstrin homology domains: calcium- and agonist-induced dynamic changes and relationship to myo-[3H]inositol-labeled phosphoinositide pools. J Cell Biol 143, 501-510.

Gerami B et al. (1997) International C. elegans Meeting "MAPPING QUANTITATIVE TRAIT LOCI FOR CHEMOTAXIS: CORRESPONDENCE BETWEEN QTL AND odr CANDIDATE LOCI"

Phillips PC, Gerami B, Morphew JJ

[International C. elegans Meeting, 1997]

Understanding the genetics of complex traits is challenging because it can be difficult to separate out the effects of the numerous genes affecting the trait. C. elegans can serve as a useful model system for studying complex traits because of the wealth of genetic and functional information available. Chemotaxis provides an ideal trait for this type of study because it ecologically important to the nematodes, as well as likely to be influenced by many genes (a number of which are known). In collaboration with Thomas Johnson and David Shook [1] and Robert Shmookler Reis and Robert Ebert [2], who provided genotyped lines generated in a cross between N2 and BO, we have assayed the chemotaxic response of 180 recombinant inbred lines to benzaldehyde at two concentrations. These concentrations, 50 nl and 500 nl, respectively lead to an attraction or repulsion response. Separate analysis of the lines from the two labs yield different results. The SR lines show a QTL mapping to the fourth chromosome, whereas the TJ lines show several QTL, primarily on the X chromosome. The QTL on X map to the same locations as two mutants known to block the response to benzaldehyde, odr-1 and odr-5 [3]. We are in the process of evaluating these candidate loci as the actual QTL using backcrossing and complementation testing approaches. Our hope is to create a model system for studying a variety of quantitative genetic questions. [1] Genetics 142:801 (1996), [2] Genetics 135:1003 (1993), [3] Bargmann et al., Cell 74:515 (1993)