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C. elegans as a model organism to study animal Behavior
안주홍 ( Joo Hong Ahnn ) 한국동물실험대체법학회 2007 한국동물실험대체법학회 학술대회집 Vol.2007 No.1
Ca2+ / calmodulin-dependent calcineurin has been shown to have important roles in various Ca2+ signaling pathways. We have previously reported that cnb-1 mutants, null mutants of a regulatory B subunit, displayed pleiotropic defects including uncoordinated movement and delayed egg laying in C. elegans. Interestingly, gain-of-function mutants of a catalytic A subunit showed exactly opposite phenotypes to those of cnb-1 mutants providing an excellent genetic model to define calcium-mediated signaling pathway at the organism level. Furthermore, calcineurin is also important for normal cuticle formation, whichis required for maintenance of normal body size in C. elegans. Genetic interactions between tax-6 and several mutants including egl-30 and egl-10 which are known to be involved in Gprotein signaling pathway suggest that calcineurin indeed regulates locomotion and serotonin-mediated egg laying through goa-1(Goα) and egl-30(Gqα). Our results indicate that, along with CaMKII, calcineurin regulates G-protein-coupled phosphorylation signaling pathways in C. elegans. The enteric muscle contraction (EMC) is the last step of the defecation behavior which occurs every 50 seconds in C. elegans. This EMC is regulated by intestinal and anal depressor muscles, which are innervatedby GABA motor neurons. Our data show that calcineurin (tax-6) is expressed in intestinal muscle and anal depressor muscle, and the gain-of-function mutant of calcineurin, tax-6(jh107), shows defects in enteric muscle contractions. In addition, exogenous GABA failed to rescue the EMC defects of tax-6(jh107) indicating that calcineurin functions in postsynaptic muscles rather than presynaptic neurons regulating EMC, which could be rescued by exogenous GABA treatment. Genetic epistasis with exp -1 mutant, which encodes an excitatory GABA receptor, suggests that calcineurin functions as a negative regulator of exp-1 in excitatory GABA signaling.
Calcineurin may regulate multiple endocytic processes in C. elegans
( Hyun Ok Song ),( Joo Hong Ahnn ) 생화학분자생물학회 2011 BMB Reports Vol.44 No.2
Calcineurin is a serine/threonine protein phosphatase controlled by Ca2+ and calmodulin that has been implicated in various signaling pathways. Previously, we reported that calcineurin regulates coelomocyte endocytosis in Caenorhabditis elegans. So far, simple and powerful in vivo approaches have been developed to study various endocytic processes in C. elegans. Using these in vivo assays, we further analyzed the endocytic phenotypes of calcineurin mutants. We observed that the calcineurin mutants were defective in apical endocytosis in the intestine as well as synaptic vesicle recycling in the nerve cord. However, we found that calcineurin mutants displayed normal receptor-mediated endocytosis in oocytes. Therefore, our results suggest that calcineurin may regulate specific sets of endocytic processes in nematode. [BMB reports 2011; 44(2): 96-101]
예쁜 꼬마 선충의 1 번 염색체에 위치하는 unc-29 유전자 좌위 주위의 jh 2 돌연변이의 유전학적 분석
정선기,안주홍 한국유전학회 2000 Genes & Genomics Vol.22 No.4
Six lethal mutations near the unc-29 locus on chromosome I of Caenorhabditis elegans have been isolated previously. Among these mutants, one particular mutant (jh2) showed interesting terminal defect, which suggest that embryos of this mutant suffer specific defects in posterior body parts during early development. As the first step to further characterize the mutation, we have performed genetic outcrossing using three genetic markers of dpy-5(e61), dpy-5(e61 ) unc-13(e1091), unc-13(e1091) lin-11(n566) in the gene cluster region near the unc-29 locus. Following the outcrosses. three-factor crosses were conducted to place the jh2 mutation on a precise genetic map near the unc-29 locus on chromosome I. The results of three-factor crosses have placed the jh2 mutation to the region between 4.41 and 4.54 map unit right from the center of chromosome I, which corresponds to approximately a 200kb region in the physical map.