scholarly journals A molecular model for self-assembly of synaptonemal complex protein SYCE3

2019 ◽  
Author(s):  
Orla M Dunne ◽  
Owen R Davies
Keyword(s):  
Synaptonemal Complex ◽  
Self Assembly ◽  
Homologous Chromosome ◽  
Molecular Model ◽  
Three Dimensional ◽  
Coiled Coil ◽  
Central Element ◽  
Domain Swap ◽  
Assembly Mechanism ◽  
Four Helical Bundle

The synaptonemal complex (SC) is a supramolecular protein assembly that mediates homologous chromosome synapsis during meiosis. This zipper-like structure assembles in a continuous manner between homologous chromosome axes, enforcing a 100-nm separation along their entire length, and providing the necessary three-dimensional framework for crossover formation. The mammalian SC is formed of eight components - SYCP1-3, SYCE1-3, TEX12 and SIX6OS1 - arranged in transverse and longitudinal structures. These largely α-helical coiled-coil proteins undergo heterotypic interactions, coupled with recursive self-assembly of SYCP1, SYCE2-TEX12, and SYCP2-SYCP3, to achieve the vast supramolecular structure of the SC. Here, we report a novel self-assembly mechanism of SC central element component SYCE3, identified through multi-angle light scattering and small-angle X-ray scattering. SYCE3 adopts a dimeric four-helical bundle structure that acts as the building block for concentration-dependent self-assembly into a series of discrete higher order oligomers. This is achieved through staggered lateral interactions between self-assembly surfaces of SYCE3 dimers, and their end-on interaction through intermolecular domain-swap between dimer folds. These mechanisms combine to achieve potentially limitless SYCE3 assembly, which particularly favours formation of dodecamers of three laterally associated domain-swap tetramers. Our findings extend the family of self-assembling proteins within the SC and provide novel means for structural stabilisation of the SC central element.

The synaptonemal complexes of Achlya recurva (Oomycetes): karyotype analysis and three-dimensional reconstruction of pachytene nuclei in antheridia and oogonia

1991 ◽  
Vol 69 (6) ◽  
pp. 1384-1395 ◽  
Author(s):  
Hobart R. Williamson ◽  
Pesach Ben Yitzchak
Keyword(s):  
Synaptonemal Complex ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolus Organizer Region ◽  
Three Dimensional ◽  
Central Element ◽  
Three Dimensional Reconstruction ◽  
Synaptonemal Complexes ◽  
Sequence Of Events ◽  
Dimensional Reconstruction

Fifteen synaptonemal complexes, as determined by three-dimensional reconstruction of serial, ultrathin sections, were present within both antheridial and oogonial zygotene and pachytene nuclei of the oomyceteous fungus Achlya recurva, thus n = 15. The present study represents the first complete reconstruction of synaptonemal complexes in the genus Achlya. The occurrence of both zygonema and pachynema was simultaneous in antheridia and oogonia. Pachytene nuclei of antheridia and oogonia are small, 13 μm3 in volume, and the average length of the synaptonemal complexes ranged from 1.9 to 4.4 μm. Lateral elements at zygotene ranged from 1.2 to 4.7 μm. Both ends of each synaptonemal complex were attached randomly to the nuclear envelope, so a bouquet formation was not observed at pachytene. In A. recurva, the dimensions of the synaptonemal complex were as follows: overall width = 270 nm; the lateral elements = 75 nm each in width and the central region = 120 nm. There was no central element and associated transverse filaments, which may be associated with development of alternative reproductive strategies other than amphimixis, as in nematodes. Of the 15 synaptonemal complexes present, only the one carrying the nucleolus organizer region could be clearly identified from one nucleus to the next. The nucleolar organizer region was on the average 0.75 μm from the telomere in both zygotene and pachytene nuclei. There were an average of three recombination nodules in each nucleus. Synaptonemal complexes have been reported in over 80 different species of fungi and related protista. Karyotypic evolution in the oomycetes and fungi may be the result of poly-ploidization, followed by cytogenetic diversification involving aneuploidy and differing degrees of polyploidy. Such a sequence of events could explain the apparent polyphyletic formation of this group. Key words: karyotype, Oomycetes, pachytene, synaptonemal complexes, three-dimensional reconstruction.

scholarly journals Addressing the Molecular Mechanism of Longitudinal Lamin Assembly Using Chimeric Fusions

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1633 ◽  
Author(s):  
Giel Stalmans ◽  
Anastasia V. Lilina ◽  
Pieter-Jan Vermeire ◽  
Jan Fiala ◽  
Petr Novák ◽  
...  
Keyword(s):  
Cell Nucleus ◽  
Molecular Model ◽  
Coiled Coil ◽  
Cross Linking ◽  
Specific Interactions ◽  
Molecular Architecture ◽  
Filament Assembly ◽  
Assembly Mechanism ◽  
Recombinant Fragments ◽  
Chemical Cross Linking

The molecular architecture and assembly mechanism of intermediate filaments have been enigmatic for decades. Among those, lamin filaments are of particular interest due to their universal role in cell nucleus and numerous disease-related mutations. Filament assembly is driven by specific interactions of the elementary dimers, which consist of the central coiled-coil rod domain flanked by non-helical head and tail domains. We aimed to investigate the longitudinal ‘head-to-tail’ interaction of lamin dimers (the so-called ACN interaction), which is crucial for filament assembly. To this end, we prepared a series of recombinant fragments of human lamin A centred around the N- and C-termini of the rod. The fragments were stabilized by fusions to heterologous capping motifs which provide for a correct formation of parallel, in-register coiled-coil dimers. As a result, we established crystal structures of two N-terminal fragments one of which highlights the propensity of the coiled-coil to open up, and one C-terminal rod fragment. Additional studies highlighted the capacity of such N- and C-terminal fragments to form specific complexes in solution, which were further characterized using chemical cross-linking. These data yielded a molecular model of the ACN complex which features a 6.5 nm overlap of the rod ends.

Three-Dimensional reconstruction of the synaptonemal complex from high-pressure frozen maize meiocytes using IVEM Tomography

1994 ◽  
Vol 52 ◽  
pp. 14-15
Author(s):  
Jennifer C. Fung ◽  
David A. Agard ◽  
John W. Sedat
Keyword(s):  
Synaptonemal Complex ◽  
Three Dimensional ◽  
Central Element ◽  
Homologous Chromosomes ◽  
Macromolecular Assembly ◽  
Dimensional Reconstruction ◽  
Protein Components ◽  
Basic Features ◽  
General Architecture ◽  
Internal Architecture

The synaptonemal complex (SC) is a key macromolecular assembly formed during meiosis of most eukaryotes. It has a crucial role in maintaining synapsis between homologous chromosomes and in ensuring proper segregation of the homologs through the establishment of functional chiasmata. Recently, biochemical and genetic efforts have begun to identify some of the protein components of the SC. As these efforts progress, a more detailed analysis of SC structure will also be needed to incorporate these new components into the overall organization of the SC.Early efforts into the analysis of SC structure have established that its general architecture is conserved throughout many organisms. The basic features found in every SC are the two lateral elements and the central element, both which run longitudinally between the homologs during the pachytene stage of prophase I. Transverse elements which run perpendicular to the homolog axis through the central region are also often found. Although the general features of the SC are conserved, the internal architecture of these components can differ.

Three-Dimensional reconstruction of the synaptonemal complex from pachytene maize meiocytes using Electron Microscopy tomography

1993 ◽  
Vol 51 ◽  
pp. 182-183
Author(s):  
Jennifer C. Fung ◽  
Bethe A. Scalettar ◽  
David A. Agard ◽  
John W. Sedat
Keyword(s):  
Electron Microscopy ◽  
Synaptonemal Complex ◽  
Chromosome Segregation ◽  
Three Dimensional ◽  
Central Element ◽  
Amorphous Structure ◽  
Two Dimensional ◽  
Homologous Chromosomes ◽  
Exact Function ◽  
Dimensional Reconstruction

The synaptonemal complex (SC) is a structure involved in the synapsis of homologous chromosomes during the prophase I stage of meiosis. Although the exact function of the complex is unknown, it has been suggested that one possible role might be to promote recombination by ensuring close synapsis of the homologous chromosomes. In addition, it is thought that the SC may also be required to convert the resulting recombination events into functional chiasmata to provide for proper chromosome segregation at the end of the first stage of meiosis.The SC structure itself is highly conserved across a variety of species. The organization of the SC is tripartite consisting of lateral, central and transverse elements. Two-dimensional cytological observations have been made to characterize the general features of these SC components. The lateral elements are 300 - 500 Å wide proteinaceous structures which flank the synapsed regions of the chromosome bivalent. Between the two lateral elements is a central region containing the central element commonly characterized as a less dense amorphous structure.

Functional self-assembling polypeptide bionanomaterials

2012 ◽  
Vol 40 (4) ◽  
pp. 629-634 ◽  
Author(s):  
Tibor Doles ◽  
Sabina Božič ◽  
Helena Gradišar ◽  
Roman Jerala
Keyword(s):  
Self Assembly ◽  
Biological Systems ◽  
Three Dimensional ◽  
Coiled Coil ◽  
Chemical Properties ◽  
Building Blocks ◽  
External Signal ◽  
Form Complex ◽  
Cell Factories ◽  
Self Assembling

Bionanotechnology seeks to modify and design new biopolymers and their applications and uses biological systems as cell factories for the production of nanomaterials. Molecular self-assembly as the main organizing principle of biological systems is also the driving force for the assembly of artificial bionanomaterials. Protein domains and peptides are particularly attractive as building blocks because of their ability to form complex three-dimensional assemblies from a combination of at least two oligomerization domains that have the oligomerization state of at least two and three respectively. In the present paper, we review the application of polypeptide-based material for the formation of material with nanometre-scale pores that can be used for the separation. Use of antiparallel coiled-coil dimerization domains introduces the possibility of modulation of pore size and chemical properties. Assembly or disassembly of bionanomaterials can be regulated by an external signal as demonstrated by the coumermycin-induced dimerization of the gyrase B domain which triggers the formation of polypeptide assembly.

scholarly journals DNA-Grafted 3D Superlattice Self-Assembly

2021 ◽  
Vol 22 (14) ◽  
pp. 7558
Author(s):  
Shuang Wang ◽  
Xiaolin Xie ◽  
Zhi Chen ◽  
Ningning Ma ◽  
Xue Zhang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Three Dimensional ◽  
Building Blocks ◽  
Material Structure ◽  
Control Material ◽  
New Methods ◽  
Assembly Mechanism ◽  
Dynamic Assembly ◽  
Material Fabrication ◽  
Grafted Nanoparticle

The exploitation of new methods to control material structure has historically been dominating the material science. The bottom-up self-assembly strategy by taking atom/molecule/ensembles in nanoscale as building blocks and crystallization as a driving force bring hope for material fabrication. DNA-grafted nanoparticle has emerged as a “programmable atom equivalent” and was employed for the assembly of hierarchically ordered three-dimensional superlattice with novel properties and studying the unknown assembly mechanism due to its programmability and versatility in the binding capabilities. In this review, we highlight the assembly strategies and rules of DNA-grafted three-dimensional superlattice, dynamic assembly by different driving factors, and discuss their future applications.

Three-Dimensional self-assembly of branching nanofibers over micro fibrous trunk by Coaxial Electrospinning

2018 ◽  
Author(s):  
Zahra Bazrafshan ◽  
George K. Stylios
Keyword(s):  
Self Assembly ◽  
Three Dimensional ◽  
The Self ◽  
Coaxial Electrospinning ◽  
Average Height ◽  
Experimental Conditions ◽  
Assembly Mechanism ◽  
Acid Soluble Collagen ◽  
One Step ◽  
3D Collagen

One step fabrication of 3D fiber stack of Acid Soluble Collagen-g-P(MMA-co-EA)/Nylon 6 formed by coaxial electrospinning is obtained through controlling the experimental conditions. The resulting 3D collagen based nanofibrous stack shows two distinguished assemblies: randomly oriented microfibers of 6.9±2.2µm diameter and dense branched nanofibers of 216±49 nm diameter. The fiber stacks can be accumulated within 20 min via single needle coaxial electrospinning. The stacks can obtain an average height of 4 cm. The self-assembly mechanism of the fiber stack and the effect of experimental conditions were also investigated. The self-assembled 3D fiber underpinned by the promising potential due to its large surface area and pore size for many practical end uses such as tissue engineering, Textiles, filtration require the properties of nanotexture of collagen based macrostructure.

Polypeptide-engineered physical hydrogels designed from the coiled-coil region of cartilage oligomeric matrix protein for three-dimensional cell culture

2014 ◽  
Vol 2 (20) ◽  
pp. 3123-3132 ◽  
Author(s):  
Ming-Hao Yao ◽  
Jie Yang ◽  
Ming-Shuo Du ◽  
Ji-Tao Song ◽  
Yong Yu ◽  
...  
Keyword(s):  
Cell Culture ◽  
Self Assembly ◽  
Cartilage Oligomeric Matrix Protein ◽  
Matrix Protein ◽  
Three Dimensional ◽  
Coiled Coil ◽  
The Self ◽  
Coiled Coil Region ◽  
Dimensional Cell

A class of physical hydrogels photo-cross-linked from multi-branched photopolymeriized monomers based on the self-assembly of coiled-coil polypeptide P is developed.

scholarly journals Structural basis of meiotic chromosome synaptic elongation through hierarchical fibrous assembly of SYCE2-TEX12

2020 ◽  
Author(s):  
James M. Dunce ◽  
Lucy J. Salmon ◽  
Owen R. Davies
Keyword(s):  
Self Assembly ◽  
Meiotic Chromosome ◽  
Coiled Coil ◽  
Building Blocks ◽  
Chromosome Length ◽  
Structural Basis ◽  
Intermediate Filament Proteins ◽  
Structural Support ◽  
Chromosome Synapsis ◽  
Assembly Mechanism

AbstractThe supramolecular structure of the synaptonemal complex (SC) mediates homologous chromosome synapsis and facilitates the formation of genetic crossovers during meiosis. The mammalian SC is formed of eight coiled-coil proteins which interact in specific subcomplexes and self-assemble into distinct macromolecular arrays that fulfil specific aspects of the SC’s dynamic functional architecture. Here, we report the structure of SC subcomplex SYCE2-TEX12 and its mechanism of self-assembly into fibres that define the SC’s midline longitudinal structure. X-ray crystal structures, electron microscopy, biophysical and mutational analyses reveal that SYCE2-TEX12 is assembled from 2:2 complexes in which TEX12 chains are positioned at either end of a rod-like SYCE2 dimer. These molecular building-blocks assemble laterally into 4:4 complexes, and longitudinally into fibres of potentially limitless length, which acts as string-like threads that wind around one another in intertwined fibres of up to 40-nm in width and several micrometres in length. This hierarchical assembly mechanism is reminiscent of intermediate filament proteins and results in SYCE2-TEX12 fibres that can span the entire chromosome length, thereby providing the underpinning structural support for SC elongation during meiotic chromosome synapsis.

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