Qi, Yingchuan et al. (2009) International Worm Meeting "Identifying genes regulating postembryonic development of DD neurons by microarray."

Qi, Yingchuan, Jin, Yishi

[International Worm Meeting, 2009]

Six "dorsal D", or DD, GABAergic ventral cord motor neurons are born in the late stage of the embryonic development. Upon hatching the axonal patterns of DDs are identical to those in older larvae and adults, and the presynaptic terminals are formed along the ventral process of the DDs. While maintaining their axonal pattern, DDs undergo synaptic remodeling by switching their presynaptic terminals from innervating the ventral muscle to innervating the dorsal muscles towards the end of the L1 stage. The timing of this DD remodeling is under the control of the heterochronic gene lin-141. In loss-of-function mutants of lin-14, the synaptic remodeling of DDs takes place precociously at early L1. To understand the mechanisms underlying DD synaptic remodeling, we carried out a microarray analysis on isolated embryonic DDs from wild type and lin-14(lf). About 3,900 genes showed differential expression between wild type and lin-14(lf) mutants. The genes defining GABA properties were not altered in lin-14(lf), indicating that lin-14 does not control DDs'' GABAergic fate specification. The number of genes up-regulated in lin-14(lf) was about the same as the number of genes down-regulated in lin-14(lf). In particular, we found that a set of acetylcholine receptor genes were up-regulated in lin-14(lf) mutant. We have focused further analysis on two genes, acr-12 and acr-14, both of which are expressed in L1 DDs2. Loss of function mutations of acr-12 or acr-14 cause no obvious DD developmental defects. However, when we expressed the hyperactive form of each acetylcholine receptor gene in DDs, we observed impaired neurite outgrowth of DDs. We found similar neurite outgrowth defects in lin-14 null animals. We are testing a hypothesis that the activity of DDs is maintained at a low level to allow initial development of DDs during embryogenesis and early L1 stage and that altering the activity level impairs the DD postembryonic development. 1.Hallam, S. J. & Jin, Y. Nature 395, 78-82 (1998). 2.Cinar, H., Keles, S. & Jin, Y. Curr Biol 15, 340-6 (2005).

Yingchuan Qi et al. (2008) C.elegans Neuronal Development Meeting "Neuronal acetylcholine receptors ACR-2 and ACR-12 subunits are required in motor neurons for coordinated locomotion"

H Horvitz, Tamara Stawicki, Yingchuan Qi, Yishi Jin

[C.elegans Neuronal Development Meeting, 2008]

Ventral cord motor neurons regulate the sinusoidal movement of the worm by generating sequential contraction and relaxation of longitudinal muscles. When muscles on one side are activated by cholinergic A- and B-type motor neurons, the muscles on the opposite side are reciprocally inhibited by GABAergic D-type motor neurons. A and B type motor neurons form dyadic synapses with muscles as one post-synaptic partner and the D-type motor neurons as the other. We are interested in understanding the cellular basis of neuronal signaling within the motor neuron circuit and have examined the roles of the acetylcholine receptor non-alpha subunit ACR-2. acr-2 is expressed in A- and B-type motor neurons. We have characterized an unusual mutation, acr-2(n2420gf), which causes hypercontraction in response to gentle touch, a ''shrinker'' phenotype resembling that of classical GABA-defective mutants such as unc-25 or unc-49. Interestingly, acr-2(n2420gf) animals also shrink spontaneously. acr-2(n2420) is predicted to produce a slow-desensitizing acetylcholine receptor that may lead to elevated presynaptic activity in A-/B- motor neurons (see abstract by Stawicki et al.). To determine the signaling components required for acr-2 function, we screened for genetic suppressors of acr-2(n2420gf). About ten suppressor mutations were found to be loss-of-function mutations of the acr-12 gene. acr-12 encodes an alpha-type acetylcholine receptor subunit that it is expressed in many neurons, including the ventral cord A-/B- and D-type motor neurons (Gottschalk et al., 2006, Cinar et al., 2005). Using cell-type specific transgene expression, we find that restoration of acr-12 expression in either A/B or D-type motor neurons is sufficient to revert the acr-12(0); acr-2(n2420gf) from the wild-type to the shrinking phenotype. These preliminary results suggest that although the acr-2(n2420gf) shrinker phenotype requires ACR-2 in A and B type neurons, its effect on locomotion may depend on the action of ACR-12 in GABAergic postsynaptic partners. Our data reveal neuronal AChRs function in cholinergic and GABAergic motorneurons to ensure correct coordination of the locomotion circuit.

Teng X et al. (2010) Cell "The apoptosome at high resolution."

Hardwick JM, Teng X

[Cell, 2010]

The mechanism by which the apoptosome activates caspases during apoptosis has been controversial. Qi et al. (2010) now present a crystal structure of a funnel-shaped octameric apoptosome complex from the nematode Caenorhabditis elegans that challenges currently held assumptions about the human apoptosome structure.

Li, Meng et al. (2019) International Worm Meeting "PAN-1 interacts with MYRF to regulate synaptic rewiring in DDs."

Xia, Shili, Qi, Yingchuan, Li, Meng, Shao, Dongyu

[International Worm Meeting, 2019]

In C. elegans, six GABAergic neurons (named DD neurons) rewire during development by reversing their axonal and dendritic domains without other obvious morphological transitions. This unique event provides an attractive system in which we can identify the molecular requirements of circuit remodeling. We have previously identified the conserved gene myrf-1 and its paralog myrf-2 as key positive regulators of DD neuron rewiring. Using immunoprecipitation of GFP::MYRF-1 from C. elegans tissues followed by quantitative mass spectrometry analyses, we have identified PAN-1 (P-granule Associated Novel protein), a novel leucine rich repeat (LRR) domain-containing protein, as an interactor of MYRF in vivo. pan-1 null mutants exhibit blocked synaptic rewiring in DD neurons. The membrane-associated isoform of PAN-1B rescues synaptic rewiring cell-autonomously. Over-expression of MYRF restores the rewiring defect of pan-1(0) mutants, indicating that PAN-1 acts upstream of MYRF.

Takayanagi-Kiya, Seika et al. (2015) International Worm Meeting "A novel mutation in the ligand-gated ion channel lgc-46 affects excitation-inhibition imbalance in the C. elegans locomotor circuit."

Cherra, Salvatore, Jin, Yishi, Qi, Yingchuan B., Takayanagi-Kiya, Seika

[International Worm Meeting, 2015]

Sinusoidal locomotion of C. elegans requires coordinated activity of excitatory and inhibitory motor neurons. The ACR-2 acetylcholine receptor is expressed in the cholinergic motor neurons, and an acr-2(gf) mutation disrupts locomotion and causes spontaneous convulsion behavior (Jospin et al. 2009). acr-2(gf) mutants display over-excitation of the cholinergic motor neurons accompanied by decreased activity of GABAergic motor neurons at the neuromuscular junctions, resulting in an imbalance in excitation (E) and inhibition (I) within the locomotor circuit. Interestingly, some human patients with Autosomal Dominant Nocturnal Frontal Lobe Epilepsy carry an identical missense mutation in the neuronal acetylcholine receptor beta2 subunit as in acr-2(gf) (Marini & Guerrin, 2007). By analyzing a large number of genetic suppressors of acr-2(gf), we have characterized several molecular pathways that modulate activity of the locomotor circuit. Here, we have identified a missense mutation in the pore-lining transmembrane domain of lgc-46, which causes suppression of acr-2(gf) convulsion. LGC-46 is a previously uncharacterized ligand-gated ion channel, closely related to the ACC ACh-gated chloride channel subfamily. lgc-46(ju825) behaves as a gain-of-function mutation, as lgc-46(null) does not show effects on acr-2(gf) convulsion. lgc-46 is expressed in the nervous system, and transgenic neuron-specific expression studies support that lgc-46 function is required in cholinergic neurons. Pharmacological analysis suggests that lgc-46(ju825) affects cholinergic release at the neuromuscular junction. We are currently determining the channel activity of LGC-46 and its functional interaction with the ACR-2 receptor. Our findings will lead to a further understanding of the regulation of E/I imbalance, and thus help conceptual advance in the treatments for human diseases caused by the impairment of neuronal activity.Ref: Jospin et al. 2009. PLoS Biol. 7(12):e1000265.; Marini and Guerrin 2007. Biochem. Pharmacol. 74:1308-1314.; Stawicki, Takayanagi-Kiya et al. 2013. PLoS Genet. 9(5):e1003472.

Qi Y et al. (2013) Bio Protoc "MiniSOG-mediated Photoablation in Caenorhabdtis elegans."

Qi Y, Xu S

[Bio Protoc, 2013]

This protocol describes a method for light-inducible cell ablation in live worms. miniSOG (mini Singlet Oxygen Generator) generates singlet oxygen upon blue light illumination (Shu et al., 2011). Mitochondrially membrane targeted miniSOG (the first 55 a. a. of C. e. tomm-20 fused at the N'-terminus of miniSOG, termed as mito-miniSOG in the following) is transgenically expressed in specific cells/tissues (Qi et al., 2012). Groups of transgenic animals are illuminated under open field fluorescence light on a compound microscope or LED light setup for photo-ablation.

Meng, Jun et al. (2017) International Worm Meeting "Myrf ER-bound transcription factors drive C. elegans synaptic plasticity via cleavage-dependent nuclear translocation."

Jin, Xia, Tao, Huaping, Dong, Meng-Qiu, Qi, Yingchuan, Witvliet, Daniel, Ma, Xiaoxia, Michell, James, Jin, Yishi, Zhu, Ming, Meng, Jun, Zhen, Mei

[International Worm Meeting, 2017]

One of the enigmatic characteristics of the developing nervous system is its ability to remodel and refine neuronal connections during its transition into a functional, mature nervous system. A striking and informative example of synaptic refinement occurs during the development of the C. elegans nervous system, in which the GABAergic dorsal D (DD) neuron reverses its axonal and dendritic domains without overt changes in morphology. The synaptic rewiring allows DD neurons to acquire new connectivity and be integrated into a more mature motor circuit. This dramatic process offers a powerful model in which we can identify genes that are essential for the developmental plasticity of neurons. We have identified myrf-1, a homologue of Myrf (Myelin regulatory factor) family transcription factors, as a key regulator of synaptic rewiring in C. elegans. MYRF-1 and its paralog MYRF-2 are functionally redundant specifically in synaptic rewiring. They co-exist in the same protein complex, and act cooperatively to regulate synaptic rewiring. We find that the MYRF proteins localize to the endoplasmic reticulum membrane, and that they are cleaved into active N-terminal fragments, which then translocate into the nucleus to drive synaptic rewiring. Over-expression of active forms of MYRF is sufficient to accelerate synaptic rewiring. MYRF-1 and MYRF-2 are the first genes identified to be indispensable for promoting synaptic rewiring in C. elegans. These findings reveal a novel molecular mechanism underlying synaptic rewiring and developmental circuit plasticity.

Bocquet-Muchembled B et al. (2001) DNA Seq "Isolation of a member of ets gene family in the polychaete annelid Perinereis cultrifera."

Bocquet-Muchembled B, Leroux R, Fontaine F, Chotteau-Lelievre A

[DNA Seq, 2001]

Numerous genes belonging to the ets gene family have been described for a few years. The founder of this family is the v-ets proto-oncogene, which is the viral counterpart of the chicken c-ets-1 proto-oncogene. Main research was carried out both on Vertebrates, Drosophila and the nematod Caenorhabditis elegans. Previously, two genes of this family named Nd ets and Nd erg, were isolated in the polychaete annelid Hediste (Nereis) diversicolor. Here we have described the isolation of one gene from the ets family in another polychaete annelid named Perinereis cultrifera. By polymerase chain reaction using degenerated primers, we have amplified an approximatively 515 pb genomic region encoding the ETS domain and another domain designed as "R" domain by Qi et al. (1992) and which can mediate transactivation. By using this method for isolating members of the ets gene family, we are going to realize a phylogenetic study of the phylum of polychaete annelids.

Chen, Fei et al. (2015) International Worm Meeting "Tuning of the RNA polymerase II CTD phosphatase SSUP-72 at internal poly(A) sites controls alternative polyadenylation in C. elegans neurons."

Fu, Xiang-Dong, Kim, John K, Li, Hairi, Khivansara, Vishal, Chun, Sang Young, Jin, Yishi, Chen, Fei, Zhou, Yu, Qi, Yingchuan B.

[International Worm Meeting, 2015]

Alternative polyadenylation (APA) plays important roles in generating transcriptome diversity under physiological and pathological conditions. However, the underlying molecular mechanisms are poorly understood. By using systematic genetic studies and genome-wide surveys of the transcriptional landscape in C. elegans, we identify an APA pathway that is required for neuron development. We show that SYDN-1, a novel nuclear protein (Van Epps et al, 2010), can antagonize SSUP-72, a Ser5 phosphatase for the RNA polymerase II (Pol II) Carboxyl-Terminal Domain (CTD), and controls the mRNA isoform production of two neuronal genes, unc-44/Ankryrin and dlk-1/MAPKKK. Exclusion of SSUP-72 activity at a strong internal poly(A) site (PAS) in unc-44 dampens its usage and allows the production of a neuron-specific ankyrin long isoform. Conversely, at the weak internal PAS of dlk-1, SSUP-72 exclusion promotes its usage and produces short isoform to control its activity. Dysregulation of unc-44 and dlk-1 mRNA isoforms impairs neuronal development. Our results demonstrate a mechanism by which tissue-specific and gene-specific APA is achieved via regulation of select internal PASs.

Wang X et al. (2010) Zhongguo Zhong Yao Za Zhi "[Expression changes of age-related genes in different aging stages of Caenorhabiditis elegans and the regulating effects of Chuanxiong extract]."

Wang D, Li L, Niu X, Wang X

[Zhongguo Zhong Yao Za Zhi, 2010]

OBJECTIVE: To explore the expression changes of age-related genes in different stages of aging and the regulating effects of Chuanxiong extract on it. METHOD: According to the different stages of aging, the experiments were tested at two time points of 2 d and 6 d. Using realtime RT-PCR (qRT-PCR) to test the expression change of aging-related genes among the groups. RESULT: Compared with the 2 d control group, the expression of age-1, daf-2, let-363 were up-regulated in the 6 d control group (P < 0.05) while the expression of ins-18, let-60, sir-2.1, sod-3 were down-regulated (P < 0.05). Compared with the 2 d administration group, the expression of age-1, daf-2, let-363 were significantly up-regulated (P < 0.01) in the 6 d administration group after treated with CXE while the expression of ins-18, let-60, sir-2.1, sod-3 were significantly down-regulated (P < 0.01). CONCLUSION: In the progress of aging, the expression of age-1, daf-2, let-363 increased, functioning as aging-promoting genes; while the expression of ins-18, let-60, sir-2.1, sod-3 decreased, functioning as longevity genes; CXE extended the lifespan through inhibiting the expression of these aging-promoting genes and increasing the expression of longevity genes, which would be the molecular mechaniSm of anti-aging of traditional Chinese medicine that can promote Qi and activate blood.