2SD-01 Introduction : cytochrome c oxidase, a case study towards quantum structural biological understanding of protein functions(2SD Sail on, Quantum Structural Biology,The 49th Annual Meeting of the Biophysical Society of Japan)
2SD-01 タンパク質機能の量子構造生物学的理解 : チトクロム酸化酵素による事例研究(2SD 量子構造生物学の出発,日本生物物理学会第49回年会(2011年度))

Shinya Yoshikawa
2011 Seibutsu Butsuri  
TheBiophysicalSociety of Japan General IncorporatedAssociation Coordination ef mitosis and morphogellesis: Role ot' a pro]enged G2 phase during chordate neural tube clesure Yosuke Ogurai, Asako Sakaue-sawano2'], Masashi Nakagawa4, Nori Satoh5, Atsushi Miyawaki2'3, yasunori Sasakurai (iShimoda Mtirine Researeh Cleniex, U}tivengit.v, of Tlsukuba, 2 RJKEN Brain Science institute, i ERATO, j[ST, 4Graduate School oj'L(fe Slrience, Uhiversity of'llyogo, 5Mdrine Genomic/s Uhit, OISD
more » ... Developmentofmulti-cellularorganismsre]iesonexecutionofcclldivisionand cell movement in propcr space and time. It is thought that these two ce]lular behaviors are incompatible because each of thern rcquires different cytoskeletal arTangement. Therefore embryonic cells must regutate their timing for coordinated embryogenesis. Using a fluorescent ubiquitination-based cell cycle indicator (Fucci). we investigated spatio-temporal cell cycle progTession patterns during neural tube closuTe in the embryos or an ascidian, Ciona intestinatis. Epidennal eel]s of Ciona divide l 1 timcs as the embryos progress from l-cel1 to the tadpole tan,al stage. We detected a long G2 phase between the 1Oth and 1 1 th ee]1 divisions. during which fusion of the left and right epidenna] layers occurred to complete neural tube c]osure. During the G2 phase, epidermal cells performed the characteristic changes of cell shape that is dependent on Factin regulation. edc25 {s probably a key regulator of the cell-cycJe progression of epidcrmal ce]ls. ATtificially shortening tlie G2 phase by overexpresshig cdc2.5 caused precocious cell division befoTe oT duTing neural tube clesure, thereby disrupting the characteristic changes of cell shape. Dclaying the precocious cell division by prelonging the S phase with a DNA rcp1icatien inhibitor aphidicolin amcliorated the eff'ects of cdc25. These results suggest that the long inLcrphase during the 1lth epiderrnal cell cyclc is required for epidermal cells to change their shapes to accomplish neuTal tube closure. 2SC-03 Takeo Horie, tiniversity qf 7)iukuba) Aseidians are primitive chordat ¢ s, and their tadpole like larvae shaTe basic body plan with vertebrate. Ascidian tadpole larvae changc its shape to be sessile adult thiough metamorphosis. During metamorphosis, the larva] central nervous systcm CCNS) is subjected to extensivc rearrangement to construct the adult CNS. In this study, we examined how the larval CNS contributes to constmct the adult CNS, by using a photoconvertible fiuorescent protein, Kaede. The fiuorescence of Kaede is green when it is translated, and the fluorescence is converted into red after irradiation with UV light. This fluorescence change is irreversible. and thus it enables us to trace the cell fates of labeled cells. We established various transgenic lines which expressing Kaede in tlie ]arva] neivous system and traced larval neural cells during metamorphosis by utilizing Kaede:s photoconversion system. We show first that most part of the ascidiun larval CNS are maintained during metarnorphosis and recruited to form the adult CNS. Second, most of the larval neurons disappear and only a subset of cholinergic motor neurons and glutamatergic neurons are retained. Third, cpendymal cetls of the larval CNS contribute to constmct the adult CNS and sorne differentiate into neurons in the adu]t CNS. An unexpccted role of ependymal cells highlighted by the present study is that tbey sen,e as neurat stcin-like ce]ls to reconstruct the adult nervous network during chordate metamorphosis. veljneevvaveSWCVesKaedeeMLveMVcogmaraWles[t6 mpaspmmKoiaftcF Tracing of the central nervous system ef ascidian larva during metamorphosiswithphotoconvertibletluorescentprotein,Kaede In normal Drosophila development, the terminalia rotates 360 degree as it fo"ns, but th{s rotation stops prematurely when apoptotic signals wcre inhibited. Imaging ai]alysis reveals that in normal flies, the speed or this rotation is vai'iable, with distinct initiation, acceleration, deceleration, and termination stages. ]nhibiting apoptotic signats result in a loss of the accelcration phase. and a failure in proper teminalia development. Through imaging anaTysis of the precess ef genitalia rotation, we hope to gain better insight into how cellular netwoTk systems ftmction in erganogenesis. 2SC-05 Kohei Hatta, Tamami Ymnamoto, Science, Universitv Imaging of chatTenging. navigation, Kaede?KikGR reactivatab!c devcloped a method to inffa-red laser pulses in thc bra{n oftransgenic animal by HSP-promoter, This methed revealed axona] navigation from area ofinteTest ill the brain, For monitorin'g physiological activities of muscles and neurons, we pcrfonned Ca2i imaging efthe whole embryo at 1 dfp with GCAMP3, a GFPbased Ca2'-indicator. It was found that the spinal cord cel]s fired in phase with the muscles en the same side during alternating tail flips. The method also revealed local slow Ca2' waves sporadically appearing during the eaTTy brain morphogenesis. Analyzing 3D structure of the embryo or bTain without dcfonnation aTong z-axis is diMcult even by two-photon scanning rnicroscopy. X-ray rnicro-tomography ceuld be more suitable to obtain this information, but in general, soft tissues are not easily imaged even after metal staining. Here we report that, by using contrast-enhanced X-ray micro-tomography in the SPring-8, arrangement of cells in the whole einbr},o or brain even without staining could be visua]ized aL near-single cetl rcsolution, epptzaffreittaic6[tUpmflmsva・ffI・vaeeop(pt-YYti Imaging ef structure, development and function ot' nervous s}'stem in a simp]e vertebrate Shinichi Okamoto, Masashi Nakagawa. Takanori Ikenaga, Yohei Nakajima, MaTiko Itoh {Craduate School ofLijb . ef'th'ogo) a whole vertcbrate embryo at single cell resolutien is still Here we discuss our effbrts to visualize morphogenesis. axonal neural circuit formation and its function, For morphogenesis, , green-to-red photo-convertible, or Dronpa. a photofluorescent proteins coald be effectively used. We aTso have induce fiuorescent proteins locally by applying focused carrying a gene regulated 2SD-Ol Shinya 2sc-o4 zaEnentbjfix6mavatmeea)sicuneth imaging analysis of cellular dynamics for organogenesis Erina Kuranaga (Lab. Histogenetic P),namics, RLIIE/V CDB) Programmed cell dcath or apoptosis is a process by which cells aTe selected for death at set times in development and is used in an adult organism to maintain homeostasis by eliminating cells that have developed abnormalitics, Apeptosis plays an important roTe in maintaining the cellular society not only by eliminating unneeded cells at givcn sites and stages, but also by other functions such as regulating the proliferation and migration oCneighboring ce11s. Our aim is to elucidate the physiological Toles of apoptosis and the basic mechanisms for regulating organogenesis using moleeular, genetic and bioimaging approaches. We havc chosen Drosophila as our model, taking advantage of its utility in deve]Dpmenta1 studies and thc vveatth ofgenetic data avai]able, To etucidate the role of cell death in developmental processes, i-,e will ana]yze the phenotypes of mutants for apoptotic signals in which the cxteTior male genitalia develeps eytcoeseenecoi+asvakta\carene:fFoaAgefk\sc[[s u$euanza lntroduction: cytochrome c oxidase, a case study towards quantumstructura]biologicalunderstandingofproteinfuncti Yoshikawa (bbeiverh'ity' of ilyogo) Cytochrome c oxidase reducces moteculur oxygen to water coupled with proten pumping. Rresonance Raman analyses shewed that the O?-bound fonn appears as the initial intermediatc during 02 reduction and that the second intermediate is an oxide fbmi bound to Fe.]4'. These results indicate that 02 is redueed to water hi one and three electron reduction steps without releasing any reactive oxygen species. X-ray structural anatysis using respiratory inhibitors for probing the function of tbe 02 reduction site provided the possible stmctural bases for the 02 reduction process as fo11ows; CuB in a trigonal planer coordination is located significalltly apart froni Fe.] and that 02 at Fc.32' gives 02LFe.33' to induce tillec possib+e eTectron transfer pathways, X-ray strueture of bovine enzyme showed that a pathway comprised of a hydrogen-bond network and a water channel in tandem pumps protons. The hydrogen-bond network is hydrogen-bonded to the formyl group ofheme a, suggesting that the net positive charge of heme a ereated upon oxidation is delocalized to the formyll group to drive the proton-act{ve transport tillough the hydrogen bond network. The dclocaljzation of the net positive charge to the forniyl group has been provcn by resonance Raman analyscs, These findings indicate that both Xray structural and vibTational spectrose{)pic analyses are indispensablc for understanding the reaction mechanism as the behavior of the valence electrons of the functional sites.
doi:10.2142/biophys.51.s16_4 fatcat:ej5imirnkbf3npsgi3xd2mcsgy