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The Expression of Human DNA Helicase B Is Affected by G-Quadruplexes in the Promoter.

ABSTRACT: G-Quadruplexes are secondary structures that can form in guanine-rich DNA and RNA that have been implicated in regulating multiple biological processes, including transcription. G-Quadruplex-forming sequences are prevalent in promoter regions of proto-oncogenes and DNA repair proteins. HELB is a human helicase involved in DNA replication and repair with 12 runs of three to four guanines in the proximal promoter. This sequence has the potential to form three canonical three-tetrad G-quadruplexes. Our results show that although all three G-quadruplexes can form, a structure containing two noncanonical G-quadruplexes with longer loops containing runs of three to four guanines is the most prevalent. These HELB G-quadruplexes are stable under physiological conditions. In cells, stabilization of the G-quadruplexes results in a decrease in the level of HELB expression, suggesting that the G-quadruplexes in the HELB promoter serve as transcriptional repressors.

SUBMITTER: Zafar MK

PROVIDER: S-EPMC7346868 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature

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The Expression of Human DNA Helicase B Is Affected by G-Quadruplexes in the Promoter.

Zafar Maroof Khan MK Hazeslip Lindsey L Chauhan Muhammad Zain MZ Byrd Alicia K AK

Biochemistry 20200607 26

G-Quadruplexes are secondary structures that can form in guanine-rich DNA and RNA that have been implicated in regulating multiple biological processes, including transcription. G-Quadruplex-forming sequences are prevalent in promoter regions of proto-oncogenes and DNA repair proteins. HELB is a human helicase involved in DNA replication and repair with 12 runs of three to four guanines in the proximal promoter. This sequence has the potential to form three canonical three-tetrad G-quadruplexes. ...[more]

PMID: 32478505

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