Non-Canonical G-quadruplexes cause the hCEB1 minisatellite instability in Saccharomyces cerevisiae

Non-Canonical G-quadruplexes cause the hCEB1 minisatellite instability in Saccharomyces cerevisiae

G-quadruplexes (G4) are polymorphic four-stranded structures formed by certain G-rich nucleic acids in vitro, but the sequence and structural features dictating their formation and function in vivo remains uncertain. Here we report a structure-function analysis of the complex hCEB1 G4-forming sequence. We isolated four G4 conformations in vitro, all of which bear unusual structural features: Fo...

Interaction among Nystatin and Penicillin G against Saccharomyces cerevisiae

Formation of pearl-necklace monomorphic G-quadruplexes in the human CEB25 minisatellite.

CEB25 is a human minisatellite locus, composed of slightly polymorphic 52-nucleotide (nt) tandem repeats. Genetically, most if not all individuals of the human population are heterozygous, carrying alleles ranging from 0.5 to 20 kb, maintained by mendelian inheritance but also subject to germline instability. To provide insights on the biological role of CEB25, we interrogated its structural f...

Bifunctional Zn(II) complexes for recognition of non-canonical thymines in DNA bulges and G-quadruplexes.

Six Zn(II) complexes of derivatives of 1,4,7,10-tetraazacyclododecane (cyclen) were studied for binding to DNA sequences containing non-canonical thymines, including a hairpin with a single thymine bulge (T-bulge) and a G-quadruplex (H-telo) containing thymine loops. The cyclen-based macrocycles contained pendents with either two fused rings to give planar groups including quinolinone (QMC), co...

Genetic instability triggered by G-quadruplex interacting Phen-DC compounds in Saccharomyces cerevisiae

G-quadruplexes are nucleic acid secondary structures for which many biological roles have been proposed but whose existence in vivo has remained elusive. To assess their formation, highly specific G-quadruplex ligands are needed. Here, we tested Phen-DC(3) and Phen-DC(6), two recently released ligands of the bisquinolinium class. In vitro, both compounds exhibit high affinity for the G4 formed ...