G-quadruplexes as novel cis-elements controlling transcription during embryonic development.

Area of Science:

• Genetics and Genomics
• Developmental Biology
• Molecular Biology

Background:

• G-quadruplexes are dynamic DNA structures found in G-rich regions.
• They are implicated in regulating cellular processes like replication and transcription.
• Their in vivo role in vertebrate embryonic development remains largely unexplored.

Purpose of the Study:

• To investigate the transcriptional role of conserved G-quadruplexes during vertebrate embryonic development.
• To identify and characterize G-quadruplexes in developmental gene promoters.
• To assess the impact of G-quadruplex disruption on gene expression and embryonic development in vivo.

Main Methods:

• In silico identification of conserved putative G-quadruplex sequences (PQSs) in human, mouse, and zebrafish developmental gene promoters.
• In vitro folding assays to confirm G-quadruplex formation.
• In cellulo studies using reporter gene assays.
• In vivo experiments involving microinjection of small ligands or complementary oligonucleotides into zebrafish embryos.

Main Results:

• Conserved PQSs were identified in promoters of developmental genes, including nog3, col2a1, and fzd5.
• Selected G-quadruplexes were shown to affect transcription in cellulo.
• In vivo disruption of G-quadruplexes led to reduced target gene transcription in zebrafish embryos.
• Phenotypic alterations in zebrafish embryos and larvae mimicked those of gene-specific morphants.

Conclusions:

• Conserved G-quadruplexes are essential regulators of gene transcription during vertebrate embryonic development.
• This study provides the first in vivo evidence for the role of G-quadruplexes in this critical biological process.
• G-quadruplexes represent a novel target for understanding and potentially modulating vertebrate development.