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Generation and characterization of new alleles of quiver (qvr) that encodes an extracellular modulator of the Shaker potassium channel
Journal article   Peer reviewed

Generation and characterization of new alleles of quiver (qvr) that encodes an extracellular modulator of the Shaker potassium channel

Hongyu Ruan, Atsushi Ueda, Xiaomin Xing, Xuxuan Wan, Benjamin Strub, Spencer Mukai, Kaan Certel, David Green, Kyle Belozerov, Wei-Dong Yao, …
Journal of neurogenetics, Vol.31(4), pp.325-336
10/02/2017
DOI: 10.1080/01677063.2017.1393076
PMCID: PMC5918287
PMID: 29117754
url
https://www.ncbi.nlm.nih.gov/pmc/articles/5918287View
Open Access

Abstract

Our earlier genetic screen uncovered a paraquat-sensitive leg-shaking mutant quiver\n1\n(qvr\n1\n), whose gene product interacts with the Shaker (Sh) K\n+\nchannel. We also mapped the qvr locus to EY04063 and noticed altered day-night activity patterns in these mutants. Such circadian behavioral defects were independently reported by another group, who employed the qvr\n1\nallele we supplied them, and attributed the extreme restless phenotype of EY04063 to the qvr gene. However, their report adopted a new noncanonical gene name sleepless (sss) for qvr. In addition to qvr\n1\nand qvr\nEY\n, our continuous effort since the early 2000s generated a number of novel recessive qvr alleles, including ethyl methanesulfonate (EMS)-induced mutations qvr\n2\nand qvr\n3\n, and P-element excision lines qvr\nip6\n(imprecise jumpout), qvr\nrv7\n, and qvr\nrv9\n(revertants) derived from qvr\nEY\n. Distinct from the original intron-located qvr\n1\nallele that generates abnormal-sized mRNAs, qvr\n2\n, and qvr\n3\nhad their lesion sites in exons 6 and 7, respectively, producing nearly normal-sized mRNA products. A set of RNA-editing sites are nearby the lesion sites of qvr\n3\nand qvr\nEY\non exon 7. Except for the revertants, all qvr alleles display a clear ether-induced leg-shaking phenotype just like Sh, and weakened climbing abilities to varying degrees. Unlike Sh, all shaking qvr alleles (except for qvr\nf01257\n) displayed a unique activity-dependent enhancement in excitatory junction potentials (EJPs) at larval neuromuscular junctions (NMJs) at very low stimulus frequencies, with qvr\nEY\ndisplaying the largest EJP and more significant NMJ overgrowth than other alleles. Our detailed characterization of a collection of qvr alleles helps to establish links between novel molecular lesions and different behavioral and physiological consequences, revealing how modifications of the qvr gene lead to a wide spectrum of phenotypes, including neuromuscular hyperexcitability, defective motor ability and activity-rest cycles.
RNA editing potassium current inactivation Shaker Ly-6/neurotoxin superfamily ether-induced leg shaking qvr/sss sleepless synaptic plasticity

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