Extreme clustering of type-1 NF1 deletion breakpoints co-locating with G-quadruplex forming sequences.
Hum Genet
; 137(6-7): 511-520, 2018 Jul.
Article
em En
| MEDLINE
| ID: mdl-29992513
ABSTRACT
The breakpoints of type-1 NF1 deletions encompassing 1.4-Mb are located within NF1-REPa and NF1-REPc, which exhibit a complex structure comprising different segmental duplications in direct and inverted orientation. Here, we systematically assessed the proportion of type-1 NF1 deletions caused by nonallelic homologous recombination (NAHR) and those mediated by other mutational mechanisms. To this end, we analyzed 236 unselected type-1 deletions and observed that 179 of them (75.8%) had breakpoints located within the NAHR hotspot PRS2, whereas 39 deletions (16.5%) had breakpoints located within PRS1. Sixteen deletions exhibited breakpoints located outside of these NAHR hotspots but were also mediated by NAHR. Taken together, the breakpoints of 234 (99.2%) of the 236 type-1 NF1 deletions were mediated by NAHR. Thus, NF1-REPa and NF1-REPc are strongly predisposed to recurrent NAHR, the main mechanism underlying type-1 NF1 deletions. We also observed a non-random overlap between type-1 NF1-deletion breakpoints and G-quadruplex forming sequences (GQs) as well as regions flanking PRDM9A binding-sites. These findings imply that GQs and PRDM9A binding-sites contribute to the clustering of type-1 deletion breakpoints. The co-location of both types of sequence was at its highest within PRS2, indicative of their synergistic contribution to the greatly increased NAHR activity within this hotspot.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Deleção de Genes
/
Neurofibromina 1
/
Quadruplex G
Limite:
Female
/
Humans
/
Male
Idioma:
En
Revista:
Hum Genet
Ano de publicação:
2018
Tipo de documento:
Article