Dhillon HS et al. (1994) Worm Breeder's Gazette "More Degenerins in the Worm?"

Dhillon HS, Driscoll MA

[Worm Breeder's Gazette, 1994]

More degenerins in the worm? Harbinder Singh Dhillon and Monica Driscoll. Department of Molecular Biology and Biochemistry, Rutgers University, Center for Advanced Biotechnology and Medicine, 679 Hoes lane, Piscataway, N.J. 08855

Nechipurenko, Inna et al. (2015) International Worm Meeting "A new role for the conserved centrosomal protein Girdin in the regulation of primary cilia biogenesis in C. elegans and mammalian cells."

Blacque, Oliver, Olivier-Mason, Anique, Sengupta, Piali, Nechipurenko, Inna, Kennedy, Julie

[International Worm Meeting, 2015]

Precise regulation of centrosome position is critical for diverse processes including asymmetric cell division, neurogenesis, directed cell migration, and ciliogenesis. Primary cilia, present on the surface of most cell types in metazoans, are key mediators of diverse signaling pathways essential for embryonic development, sensory signal transduction, and adult tissue homeostasis. Cilia from all studied organisms share a conserved core organization comprised of a microtubule-based axoneme anchored by the basal body (BB) and surrounded by a specialized membrane. Primary cilium assembly is a multi-step process that relies on mother centriole-to-BB transition, BB migration and anchoring to membrane, establishment of the 'ciliary gate', and axoneme elongation from the BB via intraflagellar transport of ciliary components. Considerable progress has been made in identifying molecular components of distinct centrosomal and ciliary sub-compartments; however, the mechanisms regulating centrosome positioning during early steps of ciliogenesis are poorly understood. We find that the highly conserved signaling protein Girdin localizes to the BB in C. elegans sensory neurons and mammalian cells. Loss of grdn-1 function in C. elegans results in defective sensory cilia morphology, ultrastructure, and localization of BB, transition zone, and signaling proteins. Similarly, Girdin knockdown in mammalian RPE-1 cells leads to a complete loss of, or shortened cilia, and dissociation of the BB from the nucleus. These findings suggest a conserved function for Girdin in regulating centrosome positioning, and thereby ciliogenesis, in both C. elegans sensory neurons and mammalian cells. Mammalian Girdin has been previously implicated in regulating the actin cytoskeleton, and in coupling multiple classes of surface receptors to downstream signaling events in different contexts (e.g. cell migration, synaptic plasticity, and tumorigenesis). Therefore, Girdin is perfectly positioned to link extracellular cues to the cytoskeleton to ensure correct centrosome/BB positioning during primary cilia formation - a previously uncharacterized role for this protein in any species. We will present our ongoing efforts to further characterize the mechanism, by which Girdin regulates BB positioning and primary cilia biogenesis in C. elegans sensory neurons and mammalian cells.

Pinheiro D et al. (2014) Dev Cell "Making the most of the midbody remnant: specification of the dorsal-ventral axis."

Bellaiche Y, Pinheiro D

[Dev Cell, 2014]

In this issue of Developmental Cell, Singh and Pohl (2014) report that myosin II cortical flow and the midbody remnant participate in the specification of the C.elegans embryo dorsal-ventral axis.

Nechipurenko IV et al. (2016) Dev Cell "A Conserved Role for Girdin in Basal Body Positioning and Ciliogenesis."

Blacque OE, Kazatskaya A, Nechipurenko IV, Olivier-Mason A, Heiman MG, Kennedy J, Sengupta P, McLachlan IG

[Dev Cell, 2016]

Primary cilia are ubiquitous sensory organelles that mediate diverse signaling pathways. Cilia position on the cell surface is determined by the location of the basal body (BB) that templates the cilium. The mechanisms that regulate BB positioning in the context of ciliogenesis are largely unknown. Here we show that the conserved signaling and scaffolding protein Girdin localizes to the proximal regions of centrioles and regulates BB positioning and ciliogenesis in Caenorhabditis elegans sensory neurons and human RPE-1 cells. Girdin depletion alters localization of the intercentriolar linker and ciliary rootlet component rootletin, and rootletin knockdown in RPE-1 cells mimics Girdin-dependent phenotypes. C.elegans Girdin also regulates localization of the apical junction component AJM-1, suggestingthat in nematodes Girdin may position BBs via rootletin- and AJM-1-dependent anchoring to the cytoskeleton and plasma membrane, respectively. Together, our results describe a conserved role for Girdin in BB positioning and ciliogenesis.

Nechipurenko IV et al. (2017) Elife "Centriolar remodeling underlies basal body maturation during ciliogenesis in Caenorhabditis elegans."

Berciu C, Sengupta P, Nicastro D, Nechipurenko IV

[Elife, 2017]

The primary cilium is nucleated by the mother centriole-derived basal body (BB) via as yet poorly characterized mechanisms. BBs have been reported to degenerate following ciliogenesis in the C. elegans embryo, although neither BB architecture nor early ciliogenesis steps have been described in this organism. In a previous study (Doroquez et al., 2014), we described the three-dimensional morphologies of sensory neuron cilia in adult C. elegans hermaphrodites at high resolution. Here, we use serial section electron microscopy and tomography of staged C. elegans embryos to demonstrate that BBs remodel to support ciliogenesis in a subset of sensory neurons. We show that centriolar singlet microtubules are converted into BB doublets which subsequently grow asynchronously to template the ciliary axoneme, visualize degeneration of the centriole core, and define the developmental stage at which the transition zone is established. Our work provides a framework for future investigations into the mechanisms underlying BB remodeling.

Lee YT et al. (2019) Dev Cell "The Bacterivore's Solution: Fight and Flight to Promote Survival."

Lee YT, Wang MC

[Dev Cell, 2019]

Bacterial avoidance and innate immune response are two ways by which C.elegans respond to pathogenic bacteria. In this issue of Developmental Cell, Kumar etal. (2019) and Singh and Aballay (2019) demonstrate that bacterial colonization is essential to induce both responses, which may be associated with somatic and reproductive longevity.

Sharma R et al. (2017) Rev Sci Tech "Canine parasitic zoonoses in India: status and issues."

Sharma R, Jenkins E, Singh B, Singh BB, Gill JPS

[Rev Sci Tech, 2017]

Dogs play valuable roles in human society. In addition to serving as pets and companions, dogs have also been important in hunting and, in recent times, as therapy animals. In India, the number of pet dogs is estimated to be around 5 million. The stray dog population in India is estimated to be 19 million and still increasing, due to ineffective control measures. Stray dogs pose substantial risks to public health due to injury and transmission of zoonoses such as rabies. Both pet and stray dogs may act as reservoirs of zoonotic parasites in India, which has a climate conducive to the environmental survival and transmission of many zoonotic parasites. At present, visceral larva migrans, cutaneous larva migrans and echinococcosis are the most important parasitic zoonoses in India. Leishmaniosis, dirofilariosis, Brugia malayi infection and giardiosis are potentially significant emerging parasitic zoonoses, and theleziosis, gnathostomiosis and dipylidiosis occur sporadically. Because of their biomedical and public health significance, and the lack of literature and compiled data on parasitic zoonoses of dogs in India, the authors provide a concise review on this topic along with potential control strategies.

Huang H et al. (2017) Bio Protoc "Measuring Caenorhabditis elegans Sleep During the Transition to Adulthood Using a Microfluidics-based System."

Hart AC, Singh K, Huang H

[Bio Protoc, 2017]

C. elegans sleep during development is regulated by genes and cellular mechanisms that are conserved across the animal kingdom (Singh et al., 2014; Trojanowski & Raizen, 2016). C. elegans developmental sleep is usually assessed during the transition to adulthood, a 2.6 h time interval called lethargus (Raizen et al., 2008; Singh et al., 2011). During lethargus, animals cycle between periods of immobility (sleep bouts) and periods of active locomotion (motion bouts). Sleep bouts resemble sleep in other species based on behavioral criteria, including cessation of feeding and locomotion, increased arousal threshold for response to sensory stimulation, rapid reversibility, and homeostatic response to sleep loss. Several assays have been developed to study sleep in C. elegans (Belfer et al., 2013; Bringmann, 2011; Nelson et al., 2013; Raizen et al., 2008). Here, we contribute a detailed protocol for assessment of C. elegans sleep during lethargus, which has been used successfully by many research groups, incorporating simple microfluidic chambers, a low cost camera with lighting system, and computational analysis based on image subtraction. We note that this system could be easily adapted to assess sleep in any small animal.

Huang, Huiyan et al. (2013) International Worm Meeting "A genetic screen for Notch downstream targets regulating C. elegans sleep."

Zhu, Chen-Tsen, Hart, Anne, Huang, Huiyan

[International Worm Meeting, 2013]

The conserved Notch signaling pathway plays well-defined roles in cell fate determination during development. Recently, Notch has also been implicated in non-developmental neuronal processes across species, including invertebrate sleep. In C. elegans, the level of Notch activity affects both quality and quantity of lethargus quiescence, a sleep-like behavior coinciding with larval molts. Also, transiently overexpressing the Notch co-ligand, OSM-11, is sufficient to drive inappropriate quiescence in adult animals, which can be suppressed by loss of either Notch receptor or downstream players in Notch signaling (Singh et al., 2011). To find pertinent transcriptional targets of the Notch pathway and to gain insight into regulation of sleep, we undertook a classical suppressor screen to identify suppressors of inappropriate quiescence in adult hsp::osm-11 animals. In this screen, 2122 mutant lines were assessed; 79 independent isolates suppressed the OSM-11-induced inappropriate quiescence. To exclude mutations with pervasive effects on locomotion, we examined endogenous L4/adult lethargus quiescence in these 79 strains using both an adaption of the Multi-Worm Tracker (Swierczek et al., 2011) and the microfluidic chamber-based assay (Singh et al., 2011). Twenty-seven strains had defects in endogenous lethargus quiescence. We are in the process of identifying the corresponding genes by whole genome sequencing. As Notch signaling also modulates sleep behavior in Drosophila (Seugnet et al., 2011), we are confident that the genes identified in this screen will be conserved regulators of arousal and sleep across species.

Kotsis F et al. (2021) Biochem Biophys Res Commun "Ift88, but not Kif3a, is required for establishment of the periciliary membrane compartment."

Kuehn EW, Boehlke C, Nitschke R, Kramer-Zucker A, Epting D, Janusch H, Lorentzen E, Neumann-Haefelin E, Viau A, Walz G, Li Y, Ganner A, Kotsis F

[Biochem Biophys Res Commun, 2021]

The primary cilium is a sensory organelle at the cell surface with integral functions in cell signaling. It contains a microtubular axoneme that is rooted in the basal body (BB) and serves as a scaffold for the movement of intraflagellar transport (IFT) particles by Kinesin-2 along the cilium. Ift88, a member of the anterograde moving IFT-B1 complex, as well as the Kinesin-2 subunit Kif3a are required for cilia formation. To facilitate signaling, the cilium restricts the access of molecules to its membrane ("ciliary gate"). This is thought to be mediated by cytoskeletal barriers ("subciliary domains") originating from the BB subdistal/distal appendages, the periciliary membrane compartment (PCMC) as well as the transition fibers and zone (TF/TZ). The PCMC is a poorly characterized membrane domain surrounding the ciliary base with exclusion of certain apical membrane proteins. Here we describe that Ift88, but not Kinesin-2, is required for the establishment of the PCMC in MDCK cells. Likewise, in C.elegans mutants of the Ift88 ortholog osm-5 fail to establish the PCMC, while Kinesin-2 deficient osm-3 mutants form PCMCs normally. Furthermore, disruption of IFT-B1 into two subcomplexes, while disrupting ciliogenesis, does not interfere with PCMC formation. Our findings suggest that cilia are not a prerequisite for the formation of the PCMC, and that separate machineries with partially overlapping functions are required for the establishment of each.