Structural basis of meiotic chromosome synaptic elongation through hierarchical fibrous assembly of SYCE2-TEX12.
Nat Struct Mol Biol
; 28(8): 681-693, 2021 08.
Article
em En
| MEDLINE
| ID: mdl-34373646
ABSTRACT
The synaptonemal complex (SC) is a supramolecular protein assembly that mediates synapsis between homologous chromosomes during meiosis. SC elongation along the chromosome length (up to 24 µm) depends on its midline α-fibrous component SYCE2-TEX12. Here, we report X-ray crystal structures of human SYCE2-TEX12 as an individual building block and on assembly within a fibrous lattice. We combine these structures with mutagenesis, biophysics and electron microscopy to reveal the hierarchical mechanism of SYCE2-TEX12 fiber assembly. SYCE2-TEX12's building blocks are 22 coiled coils that dimerize into 44 hetero-oligomers and interact end-to-end and laterally to form 10-nm fibers that intertwine within 40-nm bundled micrometer-long fibers that define the SC's midline structure. This assembly mechanism bears striking resemblance with intermediate filament proteins vimentin, lamin and keratin. Thus, SYCE2-TEX12 exhibits behavior typical of cytoskeletal proteins to provide an α-fibrous SC backbone that structurally underpins synaptic elongation along meiotic chromosomes.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Complexo Sinaptonêmico
/
Proteínas de Ciclo Celular
/
Pareamento Cromossômico
Limite:
Humans
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article