Ansley SJ et al. (2003) Nature "Basal body dysfunction is a likely cause of pleiotropic Bardet-Biedl syndrome."

Ross AJ, Johnsen RC, Ansley SJ, Cavender JC, Badano JL, Hoskins BE, Lewis RA, Mah AK, Katsanis N, Teslovich TM, Leitch CC, Beales PL, Blacque OE, Kim JC, Leroux MR, Eichers ER, Hill J

[Nature, 2003]

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous disorder characterized primarily by retinal dystrophy, obesity, polydactyly, renal malformations and learning disabilities. Although five BBS genes have been cloned, the molecular basis of this syndrome remains elusive. Here we show that BBS is probably caused by a defect at the basal body of ciliated cells. We have cloned a new BBS gene, BBS8, which encodes a protein with a prokaryotic domain, pilF, involved in pilus formation and twitching mobility. In one family, a homozygous null BBS8 mutation leads to BBS with randomization of left-right body axis symmetry, a known defect of the nodal cilium. We have also found that BBS8 localizes specifically to ciliated structures, such as the connecting cilium of the retina and columnar epithelial cells in the lung. In cells, BBS8 localizes to centrosomes and basal bodies and interacts with PCM1, a protein probably involved in ciliogenesis. Finally, we demonstrate that all available Caenorhabditis elegans BBS homologues are expressed exclusively in ciliated neurons, and contain regulatory elements for RFX, a transcription factor that modulates the expression of genes associated with ciliogenesis and intraflagellar transport.

Badano JL et al. (2003) Am J Hum Genet "Identification of a novel Bardet-Biedl syndrome protein, BBS7, that shares structural features with BBS1 and BBS2."

Lewis RA, Katsanis N, Badano JL, Ansley SJ, Leitch CC, Lupski JR

[Am J Hum Genet, 2003]

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous disorder, the primary features of which include obesity, retinal dystrophy, polydactyly, hypogenitalism, learning difficulties, and renal malformations. Conventional linkage and positional cloning have led to the mapping of six BBS loci in the human genome, four of which (BBS1, BBS2, BBS4, and BBS6) have been cloned. Despite these advances, the protein sequences of the known BBS genes have provided little or no insight into their function. To delineate functionally important regions in BBS2, we performed phylogenetic and genomic studies in which we used the human and zebrafish BBS2 peptide sequences to search dbEST and the translation of the draft human genome. We identified two novel genes that we initially named "BBS2L1" and "BBS2L2" and that exhibit modest similarity with two discrete, overlapping regions of BBS2. In the present study, we demonstrate that BBS2L1 mutations cause BBS, thereby defining a novel locus for this syndrome, BBS7, whereas BBS2L2 has been shown independently to be BBS1. The motif-based identification of a novel BBS locus has enabled us to define a potential functional domain that is present in three of the five known BBS proteins and, therefore, is likely to be important in the pathogenesis of this complex syndrome.

Blacque OE et al. (2005) Curr Biol "Functional genomics of the cilium, a sensory organelle."

Warner A, Li C, Moerman DG, Swoboda P, Khattra J, Jones SJM, Perens EA, McKay SJ, Holt RA, Mah AK, Baillie DL, Shaham S, Inglis PN, Leroux MR, Ou G, Huang P, Boroevich KA, Marra MA, Blacque OE

[Curr Biol, 2005]

Cilia and flagella play important roles in many physiological processes, including cell and fluid movement, sensory perception, and development [Scholey, 2003]. The biogenesis and maintenance of cilia depend on intraflagellar transport (IFT), a motility process that operates bidirectionally along the ciliary axoneme [Scholey, 2003; Rosenbaum et al., 2002]. Disruption in IFT and cilia function causes several human disorders, including polycystic kidneys, retinal dystrophy, neurosensory impairment, and Bardet-Biedl syndrome (BBS) [Pazour et al., 2002; Katsanis et al., 2001; Ansley et al., 2003]. To uncover new ciliary components, including IFT proteins, we compared C. elegans ciliated neuronal and nonciliated cells through serial analysis of gene expression (SAGE) and screened for genes potentially regulated by the ciliogenic transcription factor, DAF-19 [Swoboda et al., 2000]. Using these complementary approaches, we identified numerous candidate ciliary genes and confirmed the ciliated-cell-specific expression of 14 novel genes. One of these, C27H5.7a, encodes a ciliary protein that undergoes IFT. As with other IFT proteins, its ciliary localization and transport is disrupted by mutations in IFT and bbs genes. Furthermore, we demonstrate that the ciliary structural defect of C. elegans dyf-13(mn396) mutants is caused by a mutation in C27H5.7a. Together, our findings help define a ciliary transcriptome and suggest that DYF-13, an evolutionarily conserved protein, is a novel core IFT component required for cilia function.

Blacque OE et al. (2004) Genes Dev "Loss of C. elegans BBS-7 and BBS-8 protein function results in cilia defects and compromised intraflagellar transport."

Quarmby LM, Johnsen RC, Blacque OE, Mahjoub MR, Audeh M, Wicks SR, Baillie DL, Li C, Leroux MR, Beales PL, Ansley SJ, Reardon MJ, Davidson WS, Mah AK, Badano JL, Plasterk RHA, Katsanis N, McCarthy J

[Genes Dev, 2004]

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous developmental disorder whose molecular basis is largely unknown. Here, we show that mutations in the Caenorhabditis elegans bbs-7 and bbs-8 genes cause structural and functional defects in cilia. C. elegans BBS proteins localize predominantly at the base of cilia, and like proteins involved in intraflagellar transport (IFT), a process necessary for cilia biogenesis and maintenance, move bidirectionally along the ciliary axoneme. Importantly, we demonstrate that BBS-7 and BBS-8 are required for the normal localization/motility of the IFT proteins OSM-5/Polaris and CHE-11, and to a notably lesser extent, CHE-2. We propose that BBS proteins play important, selective roles in the assembly and/or function of IFT particle components. Our findings also suggest that some of the cardinal and secondary symptoms of BBS, such as obesity, diabetes, cardiomyopathy, and learning defects may result from cilia dysfunction.

Fan Y et al. (2004) Nat Genet "Mutations in a member of the Ras superfamily of small GTP-binding proteins causes Bardet-Biedl syndrome."

Blacque OE, Fan Y, Ansley SJ, Davidson WS, Baillie DL, Leroux MR, Van Haelst MM, Ross AJ, Green JS, Katsanis N, Parfrey PS, Beales PL, Compton DS, May-Simera H, Badano JL, Boroevich K, Moore SJ, Esmail MA, Lewis RA

[Nat Genet, 2004]

RAB, ADP-ribosylation factors (ARFs) and ARF-like (ARL) proteins belong to the Ras superfamily of small GTP-binding proteins and are essential for various membrane-associated intracellular trafficking processes. None of the approximately 50 known members of this family are linked to human disease. Using a bioinformatic screen for ciliary genes in combination with mutational analyses, we identified ARL6 as the gene underlying Bardet-Biedl syndrome type 3, a multisystemic disorder characterized by obesity, blindness, polydactyly, renal abnormalities and cognitive impairment. We uncovered four different homozygous substitutions in ARL6 in four unrelated families affected with Bardet-Biedl syndrome, two of which disrupt a threonine residue important for GTP binding and function of several related small GTP-binding proteins. Analysis of the Caenorhabditis elegans ARL6 homolog indicates that it is specifically expressed in ciliated cells, and that, in addition to the postulated cytoplasmic functions of ARL proteins, it undergoes intraflagellar transport. These findings implicate a small GTP-binding protein in ciliary transport and the pathogenesis of a pleiotropic disorder.

Glock C et al. (2015) Methods Mol Biol "Microbial Rhodopsin Optogenetic Tools: Application for Analyses of Synaptic Transmission and of Neuronal Network Activity in Behavior."

Glock C, Gottschalk A, Nagpal J

[Methods Mol Biol, 2015]

Optogenetics was introduced as a new technology in the neurosciences about a decade ago (Zemelman et al., Neuron 33:15-22, 2002; Boyden et al., Nat Neurosci 8:1263-1268, 2005; Nagel et al., Curr Biol 15:2279-2284, 2005; Zemelman et al., Proc Natl Acad Sci USA 100:1352-1357, 2003). It combines optics, genetics, and bioengineering to render neurons sensitive to light, in order to achieve a precise, exogenous, and noninvasive control of membrane potential, intracellular signaling, network activity, or behavior (Rein and Deussing, Mol Genet Genomics 287:95-109, 2012; Yizhar et al., Neuron 71:9-34, 2011). As C. elegans is transparent, genetically amenable, has a small nervous system mapped with synapse resolution, and exhibits a rich behavioral repertoire, it is especially open to optogenetic methods (White et al., Philos Trans R Soc Lond B Biol Sci 314:1-340, 1986; De Bono et al., Optogenetic actuation, inhibition, modulation and readout for neuronal networks generating behavior in the nematode Caenorhabditis elegans, In: Hegemann P, Sigrist SJ (eds) Optogenetics, De Gruyter, Berlin, 2013; Husson et al., Biol Cell 105:235-250, 2013; Xu and Kim, Nat Rev Genet 12:793-801, 2011). Optogenetics, by now an "exploding" field, comprises a repertoire of different tools ranging from transgenically expressed photo-sensor proteins (Boyden et al., Nat Neurosci 8:1263-1268, 2005; Nagel et al., Curr Biol 15:2279-2284, 2005) or cascades (Zemelman et al., Neuron 33:15-22, 2002) to chemical biology approaches, using photochromic ligands of endogenous channels (Szobota et al., Neuron 54:535-545, 2007). Here, we will focus only on optogenetics utilizing microbial rhodopsins, as these are most easily and most widely applied in C. elegans. For other optogenetic tools, for example the photoactivated adenylyl cyclases (PACs, that drive neuronal activity by increasing synaptic vesicle priming, thus exaggerating rather than overriding the intrinsic activity of a neuron, as occurs with rhodopsins), we refer to other literature (Weissenberger et al., J Neurochem 116:616-625, 2011; Steuer Costa et al., Photoactivated adenylyl cyclases as optogenetic modulators of neuronal activity, In: Cambridge S (ed) Photswitching proteins, Springer, New York, 2014). In this chapter, we will give an overview of rhodopsin-based optogenetic tools, their properties and function, as well as their combination with genetically encoded indicators of neuronal activity. As there is not "the" single optogenetic experiment we could describe here, we will focus more on general concepts and "dos and don'ts" when designing an optogenetic experiment. We will also give some guidelines on which hardware to use, and then describe a typical example of an optogenetic experiment to analyze the function of the neuromuscular junction, and another application, which is Ca(2+) imaging in body wall muscle, with upstream neuronal excitation using optogenetic stimulation. To obtain a more general overview of optogenetics and optogenetic tools, we refer the reader to an extensive collection of review articles, and in particular to volume 1148 of this book series, "Photoswitching Proteins."