Structural Dynamics Role of AGG Interruptions in Inhibition CGG Repeat Expansion Associated with Fragile X Syndrome.
ACS Chem Neurosci
; 15(2): 230-235, 2024 01 17.
Article
em En
| MEDLINE
| ID: mdl-38133821
ABSTRACT
Abnormal expansion of trinucleotide CGG repeats is responsible for Fragile X syndrome. AGG interruptions in CGG repeat tracts were found in most healthy individuals, suggesting a crucial role in preventing disease-prone repeat expansion. Previous biophysics studies emphasize a difference in the secondary structure affected by AGG interruptions. However, the mechanism of how AGG interruptions impede repeat expansion remains elusive. We utilized single-molecule fluorescence resonance energy transfer spectroscopy to investigate the structural dynamics of CGG repeats and their AGG-interrupted variants. Tandem CGG repeats fold into a stem-loop hairpin structure with the capability to undergo a conformational rearrangement to modulate the length of the overhang. However, this conformational rearrangement is much more retarded when two AGG interruptions are present. Considering the significance of hairpin slippage in repeat expansion, we present a molecular basis suggesting that the internal loop created by two AGG interruptions acts as a barrier, obstructing the hairpin slippage reconfiguration. This impediment potentially plays a crucial role in curbing abnormal expansion, thereby contributing to the genomic stability.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Síndrome do Cromossomo X Frágil
Limite:
Humans
Idioma:
En
Revista:
ACS Chem Neurosci
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Taiwan