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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6
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Publication Open Access Terminal neuron localization to the upper cortical plate is controlled by the transcription factor NEUROD2(Nature Publishing Group (NPG), 2019) Department of Molecular Biology and Genetics; Department of Physics; Akkaya, Cansu; Atak, Dila; Güzelsoy, Gizem; Dunn, Cory David; Dunn, Gülayşe İnce; Kabakçıoğlu, Alkan; Master Student; Faculty Member; Faculty Member; Faculty Member; Department of Molecular Biology and Genetics; Department of Physics; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; N/A; N/A; 105301; N/A; 49854Excitatory neurons of the mammalian cerebral cortex are organized into six functional layers characterized by unique patterns of connectivity, as well as distinctive physiological and morphological properties. Cortical layers appear after a highly regulated migration process in which cells move from the deeper, proliferative zone toward the superficial layers. Importantly, defects in this radial migration process have been implicated in neurodevelopmental and psychiatric diseases. Here we report that during the final stages of migration, transcription factor Neurogenic Differentiation 2 (Neurod2) contributes to terminal cellular localization within the cortical plate. In mice, in utero knockdown of Neurod2 resulted in reduced numbers of neurons localized to the uppermost region of the developing cortex, also termed the primitive cortical zone. Our ChIP-Seq and RNA-Seq analyses of genes regulated by NEUROD2 in the developing cortex identified a number of key target genes with known roles in Reelin signaling, a critical regulator of neuronal migration. Our focused analysis of regulation of the Reln gene, encoding the extracellular ligand REELIN, uncovered NEUROD2 binding to conserved E-box elements in multiple introns. Furthermore, we demonstrate that knockdown of NEUROD2 in primary cortical neurons resulted in a strong increase in Reln gene expression at the mRNA level, as well as a slight upregulation at the protein level. These data reveal a new role for NEUROD2 during the late stages of neuronal migration, and our analysis of its genomic targets offers new genes with potential roles in cortical lamination.Publication Open Access Centrosomal and ciliary targeting of CCDC66 requires cooperative action of centriolar satellites, microtubules and molecular motors(Nature Publishing Group (NPG), 2019) Department of Molecular Biology and Genetics; Department of Molecular Biology and Genetics; College of Sciences; Graduate School of Sciences and EngineeringMammalian centrosomes and cilia play key roles in many cellular processes and their deregulation is linked to cancer and ciliopathies. Spatiotempora I regulation of their biogenesis and function in response to physiological stimuli requires timely protein targeting. This can occur by different pathways, including microtubule-dependent active transport and via centriolar satellites, which are key regulators of cilia assembly and signaling. How satellites mediate their functions and their relationship with other targeting pathways is currently unclear. To address this, we studied retinal degeneration gene product CCDC66, which localizes to centrosomes, cilia, satellites and microtubules and functions in ciliogenesis. FRAP experiments showed that its centrosomal pool was dynamic and the ciliary pool associated with the ciliary axoneme and was stable. Centrosomal CCDC66 abundance and dynamics required microtubule-dependent active transport and tethering, and was inhibited by sequestration at satellites. Systematic quantitation of satellite dynamics identified only a small fraction to display microtubule- based bimodal motility, consistent with trafficking function. Majority displayed diffusive motility with unimodal persistence, supporting sequestration function. Together, our findings reveal new mechanisms of communication between membrane-less compartments.Publication Open Access Structural insight into host plasma membrane association and assembly of HIV-1 matrix protein(Nature Publishing Group (NPG), 2021) Çiftçi, Halilibrahim; Tateishi, Hiroshi; Koiwai, Kotaro; Koga, Ryoko; Anraku, Kensaku; Monde, Kazuaki; Destan, Ebru; Yüksel, Büşra; Ayan, Esra; Yıldırım, Günseli; Yığın, Merve; Sierra, Raymond G.; Yoon, Chun Hong; Su, Zhen; Liang, Mengling; Acar, Burçin; Haliloğlu, Türkan; Otsuka, Masami; Yumoto, Fumiaki; Fujita, Mikako; Senda, Toshiya; Department of Molecular Biology and Genetics; Demirci, Hasan; Dağ, Çağdaş; Güven, Ömür; Ertem, Fatma Betül; Faculty Member; Faculty Member; Department of Molecular Biology and Genetics; Koç Üniversitesi İş Bankası Enfeksiyon Hastalıkları Uygulama ve Araştırma Merkezi (EHAM) / Koç University İşbank Center for Infectious Diseases (KU-IS CID); College of Sciences; Graduate School of Sciences and Engineering; 307350; N/A; N/A; N/A; N/A; N/AOligomerization of Pr55(Gag) is a critical step of the late stage of the HIV life cycle. It has been known that the binding of IP6, an abundant endogenous cyclitol molecule at the MA domain, has been linked to the oligomerization of Pr55(Gag). However, the exact binding site of IP6 on MA remains unknown and the structural details of this interaction are missing. Here, we present three high-resolution crystal structures of the MA domain in complex with IP6 molecules to reveal its binding mode. Additionally, extensive Differential Scanning Fluorimetry analysis combined with cryo- and ambient-temperature X-ray crystallography and GNM-based transfer entropy calculations identify the key residues that participate in IP6 binding. Our data provide novel insights about the multilayered HIV-1 virion assembly process that involves the interplay of IP6 with PIP2, a phosphoinositide essential for the binding of Pr55(Gag) to membrane. IP6 and PIP2 have neighboring alternate binding sites within the same highly basic region (residues 18-33). This indicates that IP6 and PIP2 bindings are not mutually exclusive and may play a key role in coordinating virion particles' membrane localization. Based on our three different IP6-MA complex crystal structures, we propose a new model that involves IP6 coordination of the oligomerization of outer MA and inner CA domain's 2D layers during assembly and budding.Publication Open Access Experimental data on novel Fe(III)-complexes containing phenanthroline derivatives for their anticancer properties(Elsevier, 2019) Matos, Cristina P.; Adıgüzel, Zelal; Yıldızhan, Yasemin; Çevik, Özge; Nunes, Patrique; Ferreira, Liliana P.; Carvalho, Maria Deus; Campos, Debora L.; Pavan, Fernando R.; Pessoa, Joao Costa; Garcia, Maria Helena; Tomaz, Ana Isabel; Correia, Isabel; Department of Molecular Biology and Genetics; Cevatemre, Buse; Önder, Tuğba Bağcı; Ayhan, Ceyda Açılan; Department of Molecular Biology and Genetics; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); School of Medicine; N/A; 184359; N/AThis dataset is related to the research article entitled “May iron(III) complexes containing phenanthroline derivatives as ligands be prospective anticancer agents?” [1]. It includes the characterization by UV–Vis absorption spectroscopy and magnetic techniques of a group of mixed ligand Fe(III) complexes bearing a tripodal aminophenolate ligand L2−, H2L = N,N-bis(2-hydroxy-3,5-dimethylbenzyl)-N-(2-pyridylmethyl)amine, and different aromatic bases (NN = 2,2′-bipyridine [Fe(L)(bipy)]PF6 (1), 1,10-phenanthroline [Fe(L)(phen)]PF6 (2), or a phenanthroline derivative co-ligand: [Fe(L)(amphen)]NO3 (3), [Fe(L)(amphen)]PF6 (3a), [Fe(L)(Clphen)]PF6 (4), [Fe(L)(epoxyphen)]PF6 (5) (where amphen = 1,10-phenanthroline-5-amine, epoxyphen = 5,6-epoxy-5,6-dihydro-1,10-phenanthroline, Clphen = 5-chloro-1,10-phenanthroline), as well as [Fe(L)(EtOH)]NO3 (6), [Fe(phen)Cl3] (7) and [Fe(amphen)Cl3] (8). Data on their hydrolytic stability in physiological buffers is shown, as well as on their interaction with calf thymus DNA by spectroscopic tools. Additionally, the anticancer efficacy and the cellular death mechanisms activated in response to these drugs in HeLa, H1299 and MDA-MB-231 cells are provided.Publication Open Access Revealing the therapeutic effects of aminolevulinate mediated femtosecond laser induced photo-chemotherapy in different cancer cells(Sciendo, 2020) Kars, Meltem Demirel; Yıldırım, Gamze; Gündoğdu, Yasemin; Gönce, Fatmanur; Ayan, Esra; Kılıç, Hamdi Şükür; Department of Molecular Biology and Genetics; Ayan, Esra; PhD Student; Department of Molecular Biology and Genetics; Graduate School of Sciences and EngineeringPhotodynamic therapy (PDT) is a photo chemotherapeutic strategy that is the application of photosensitizing agent and light on disease or tumor site. The aim of this study is to confirm the feasibility for femtosecond (fs) laser for aminolevulinate (ALA) mediated PDT on skin, breast and bladder cancer cells. Also the remarkable aspects of ALA mediated and laser induced PDT with respect to other literally known applications were investigated. Metastatic melanoma cells SK-MEL30, mammary epithelial carcinoma cells MCF-7 and bladder cancer cells UMUC-3 were treated with ALA and then the cells were irradiated by fs laser at thirty wavelengths in between 230 and 800 nm for 30s and 60s. Anti-cancer effects of ALA phototherapy on different cancer cell lines were determined. Protoporphyrin IX (PpIX) accumulation was visualized by confocal microscopy. The effective PDT wavelengths were applied to evaluate the degree of apoptosis and necrosis in cells. The viability tests demonstrated that wavelengths 400-440 nm and 600-630 nm were found to decrease the viability on three model cell lines. PDT at 630 nm exerted cell death by necrosis and apoptosis after 30 s and 60 s periods. This paper confirms that ALA and femtosecond laser mediated PDT may be used together as therapeutic and diagnostic method to target breast, skin and urinary bladder cancer cells. The use of fs laser allows the flexibility for optimization of wavelength for photosensitizing agents.Publication Open Access Cooperative allostery and structural dynamics of streptavidin at cryogenic- and ambient-temperature(Springer Nature, 2022) Yefanov, Oleksandr M.; Barty, Anton; Tolstikova, Alexandra; Ketawala, Gihan K.; Botha, Sabine; Dao, E. Han; Hayes, Brandon; Liang, Mengning; Seaberg, Matthew H.; Hunter, Mark S.; Batyuk, Alexander; Mariani, Valerio; Su, Zhen; Poitevin, Frederic; Yoon, Chun Hong; Kupitz, Christopher; Cohen, Aina; Doukov, Tzanko; Sierra, Raymond G.; Department of Molecular Biology and Genetics; Dağ, Çağdaş; Ayan, Esra; Yüksel, Büşra; Destan, Ebru; Ertem, Fatma Betül; Yıldırım, Günseli; Eren, Meryem; Demirci, Hasan; Faculty Member; PhD Student; Faculty Member; Department of Molecular Biology and Genetics; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; N/A; N/A; N/A; N/A; 307350Ayan et al. report two structures of the protein streptavidin - one at ambient temperature determined using serial femtosecond crystallography and a second one determined at cryogenic temperature. These results provide insights into the structural dynamics of apo streptavidin and reveal a cooperative allostery between monomers for binding to biotin, and the findings are supported by GNM analysis. Multimeric protein assemblies are abundant in nature. Streptavidin is an attractive protein that provides a paradigm system to investigate the intra- and intermolecular interactions of multimeric protein complexes. Also, it offers a versatile tool for biotechnological applications. Here, we present two apo-streptavidin structures, the first one is an ambient temperature Serial Femtosecond X-ray crystal (Apo-SFX) structure at 1.7 angstrom resolution and the second one is a cryogenic crystal structure (Apo-Cryo) at 1.1 angstrom resolution. These structures are mostly in agreement with previous structural data. Combined with computational analysis, these structures provide invaluable information about structural dynamics of apo streptavidin. Collectively, these data further reveal a novel cooperative allostery of streptavidin which binds to substrate via water molecules that provide a polar interaction network and mimics the substrate biotin which displays one of the strongest affinities found in nature.Publication Open Access Structure-based design and classifications of small molecules regulating the circadian rhythm period(Nature Portfolio, 2021) Yılmaz, Fatma; Öztürk, Nuri; Department of Industrial Engineering; Department of Chemical and Biological Engineering; Department of Molecular Biology and Genetics; Türkay, Metin; Rahim, Fatih; Gül, Şeref; Kavaklı, İbrahim Halil; Işın, Şafak; Faculty Member; Researcher; Faculty Member; Department of Industrial Engineering; Department of Chemical and Biological Engineering; Department of Molecular Biology and Genetics; College of Engineering; Graduate School of Sciences and Engineering; 24956; N/A; N/A; 40319; N/ACircadian rhythm is an important mechanism that controls behavior and biochemical events based on 24 h rhythmicity. Ample evidence indicates disturbance of this mechanism is associated with different diseases such as cancer, mood disorders, and familial delayed phase sleep disorder. Therefore, drug discovery studies have been initiated using high throughput screening. Recently the crystal structures of core clock proteins (CLOCK/BMAL1, Cryptochromes (CRY), Periods), responsible for generating circadian rhythm, have been solved. Availability of structures makes amenable core clock proteins to design molecules regulating their activity by using in silico approaches. In addition to that, the implementation of classification features of molecules based on their toxicity and activity will improve the accuracy of the drug discovery process. Here, we identified 171 molecules that target functional domains of a core clock protein, CRY1, using structure-based drug design methods. We experimentally determined that 115 molecules were nontoxic, and 21 molecules significantly lengthened the period of circadian rhythm in U2OS cells. We then performed a machine learning study to classify these molecules for identifying features that make them toxic and lengthen the circadian period. Decision tree classifiers (DTC) identified 13 molecular descriptors, which predict the toxicity of molecules with a mean accuracy of 79.53% using tenfold cross-validation. Gradient boosting classifiers (XGBC) identified 10 molecular descriptors that predict and increase in the circadian period length with a mean accuracy of 86.56% with tenfold cross-validation. Our results suggested that these features can be used in QSAR studies to design novel nontoxic molecules that exhibit period lengthening activity.Publication Open Access Diffraction data from aerosolized Coliphage PR772 virus particles imaged with the Linac Coherent Light Source(Nature Publishing Group (NPG), 2020) Li, H.; Nazari, R.; Abbey, B.; Alvarez, R.; Aquila, A.; Ayyer, K.; Barty, A.; Berntsen, P.; Bielecki, J.; Pietrini, A.; Bucher, M.; Carini, G.; Chapman, H. N.; Contreras, A.; Daurer, B. J.; Flűckiger, L.; Frank, M.; Hajdu, J.; Hantke, M. F.; Hogue, B. G.; Hosseinizadeh, A.; Hunter, M. S.; Jönsson, H. O.; Kirian, R. A.; Kurta, R. P.; Loh, D.; Maia, F. R. N. C.; Mancuso, A. P.; Morgan, A. J.; McFadden, M.; Muehlig, K.; Munke, A.; Reddy, H. K. N.; Nettelblad, C.; Ourmazd, A.; Rose, M.; Schwander, P.; Marvin, Seibert M.; Sellberg, J. A.; Sierra, R. G.; Sun, Z.; Svenda, M.; Vartanyants, I. A.; Walter, P.; Westphal, D.; Williams, G.; Xavier, P. L.; Yoon, C. H.; Zaare, S.; Department of Molecular Biology and Genetics; Demirci, Hasan; Faculty Member; Department of Molecular Biology and Genetics; College of Sciences; 307350Single Particle Imaging (SPI) with intense coherent X-ray pulses from X-ray free-electron lasers (XFELs) has the potential to produce molecular structures without the need for crystallization or freezing. Here we present a dataset of 285,944 diffraction patterns from aerosolized Coliphage PR772 virus particles injected into the femtosecond X-ray pulses of the Linac Coherent Light Source (LCLS). Additional exposures with background information are also deposited. The diffraction data were collected at the Atomic, Molecular and Optical Science Instrument (AMO) of the LCLS in 4 experimental beam times during a period of four years. The photon energy was either 1.2 or 1.7 keV and the pulse energy was between 2 and 4 mJ in a focal spot of about 1.3 μm x 1.7 μm full width at half maximum (FWHM). The X-ray laser pulses captured the particles in random orientations. The data offer insight into aerosolised virus particles in the gas phase, contain information relevant to improving experimental parameters, and provide a basis for developing algorithms for image analysis and reconstruction.