Why are G quartets found in telomeres?
Telomeres, rich in guanine and with a propensity to form g-quadruplexes, are located at the terminal ends of chromosomes and help maintain genome integrity by protecting these vulnerable terminal ends from instability.
How do you make G quadruplex?
Telomeric DNA can fold into compact G-quadruplex structures involving the interaction of four guanine bases in a square planar arrangement stabilized by central cations10. G-quadruplexes can form from one, two or four strands of DNA in a parallel or antiparallel orientation11.
What is AG quadruplex?
G-quadruplexes are noncanonical nucleic acid structures formed from stacked guanine tetrads. They are frequently used as building blocks and functional elements in fields such as synthetic biology and also thought to play widespread biological roles.
What is telomeric DNA and why is it important?
Telomeres, the specific DNA–protein structures found at both ends of each chromosome, protect genome from nucleolytic degradation, unnecessary recombination, repair, and interchromosomal fusion. Telomeres therefore play a vital role in preserving the information in our genome.
Where are G-quadruplexes located in the human transcriptome?
Previous studies have reported an abundance of G4 in specific locations in genes, such as the 5′UTR, the 3′UTR and in the splice sites (5,12,16).
What are G Tetrads?
In molecular biology, a guanine tetrad (also known as a G-tetrad or G-quartet) is a structure composed of four guanine bases in a square planar array. They most prominently contribute to the structure of G-quadruplexes, where their hydrogen bonding stabilizes the structure.
Where are G-quadruplexes found?
the transcriptome
The present study shows that rG4 are widely present in the transcriptome and in all known classes of transcripts, with 60% of transcripts having at least one pG4. Several studies have been performed in order to evaluate the number of pG4 sequences in genomes and transcriptomes.
What is G rich sequence?
G-rich sequences (GRSs) capable of forming G-quadruplexes are found in the vicinity of polyadenylation regions and are involved in regulating 3′ end processing of mammalian pre-mRNAs.
What is telomeric DNA?
A telomere is a region of repetitive DNA sequences at the end of a chromosome. Telomeres protect the ends of chromosomes from becoming frayed or tangled. Each time a cell divides, the telomeres become slightly shorter. Eventually, they become so short that the cell can no longer divide successfully, and the cell dies.
What types of DNA RNA sequences can or are more likely to fold a G quadruplex?
Guanine-rich DNA sequences can fold into four-stranded, noncanonical secondary structures called G-quadruplexes (G4s).
Where are G quadruplexes found?
What types of DNA RNA sequences can or are more likely to fold a G-quadruplex?
Where is telomeric DNA located?
The telomere is a nucleoprotein complex located at the ends of eukaryotic chromosomes. It is essential for maintaining the integrity of the genome. It is not a linear structure and, for much of the cell cycle, telomeric DNA is maintained in a loop structure, which serves to protect the vulnerable ends of chromosomes.
What is telomeric replication?
The ends of the linear chromosomes are known as telomeres: repetitive sequences that code for no particular gene. These telomeres protect the important genes from being deleted as cells divide and as DNA strands shorten during replication.
What is the function of the G quadruplex?
G-Quadruplex function. The potential positive and negative roles of quadruplexes in telomere replication and function remains controversial. T-loops and G-quadruplexes are described as the two tertiary DNA structures that protect telomere ends and regulate telomere length.
Are G-quadruplexes relevant to telomere replication and function?
The direct visualization of G-quadruplex structures in human cells as well as the co-crystal structure of an RNA helicase bound to a G-quadruplex have provided important confirmations of their relevance to cell biology. The potential positive and negative roles of quadruplexes in telomere replication and function remains controversial.
What is a G-quadruplex secondary structure?
In molecular biology, G-quadruplex secondary structures (G4) are formed in nucleic acids by sequences that are rich in guanine.
Where are G-quadruplex structures found in human DNA?
Along with the association of G-quadruplexes in telomeric regions of DNA, G-quadruplex structures have been identified in various human proto-oncogene promoter regions. The structures most present in the promoter regions of these oncogenes tend to be parallel-stranded G-quadruplex DNA structures.