MAY 17, 2016 9:03 AM PDT

Forming and Unfolding Four-Stranded DNA

WRITTEN BY: Kara Marker
Although the genetic code is famous for its double helix and not its quadruple helix, it is known to occur in other forms. In a new study scientists from Umea University have demonstrated the ability of helicases breaking down a four-stranded DNA structure in the yeast species Schizosaccharomyces pombe.
 
G4 structure in DNA of human telomere

S. pombe contains regions of DNA with greater than normal levels of guanine which can form four-stranded DNA, also known as G4 structures. S. pombe is known as “fission yeast,” a single-celled free-living fungus that is commonly used as a model organism for its easy of genetic manipulation. Scientists use S. pombe for a variety of studies: cell-cycle control, mitosis and meiosis, DNA repair and recombination, and the checkpoint controls important for stability (Nature). The ribosomal and telomeric DNA regions especially have a “strong tendency” to form these structures, and scientists also have evidence of G4 structures in humans.

The formation of four-stranded DNA occurs because of guanine-rich DNA sequences. Guanine is a purine nucleobase that pairs with adenine to form conjugated double bonds in DNA and RNA, alongside pairs of adenine and thymine in DNA and adenine and uracil in RNA (PubChem).

Forming G4 structures is harmless as long as helicases are capable of unfolding them, and the present study identified motor protein Phf1 as the helicase that fulfills this requirement. G4 structures in the genome provide specific functions relating to gene expression regulation. However, scientists realize that if G4 structures “exist continuously in the genome,” they can inhibit important processes.

Pfh1 protein works to unfold G4 structures, preventing their continuous existence, by binding to specific guanine-rich DNA sequences, as scientists in this study saw from biochemical and biophysical methods and cell analyses. Unfolding efficiency is necessary to “secure the integrity of the genome during DNA replication.”

Without the proper helicase protein to unfold G4 structures, vital processes in the cells could be inhibited, and the scientists believe DNA replication could be one of the processes. More studies will need to be completed to know for sure, but scientists believe that obstruction of vital processes by G4 structures could be associated with disease development in cancer and neurodegenerative diseases. 

"An interesting research area is the development of molecules with the specific ability to bind to and stabilize G4 structures,” said Nasim Sabouri, PhD, from Umea University. “This could potentially be used to turn off the expression of certain genes that are involved in tumour formations.”

This study was recently published in the journal Nucleic Acids Research.
 

Sources: Nature, PubChem, Umea University
 
About the Author
I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
You May Also Like
NOV 10, 2022
Genetics & Genomics
Human or Host? Parasites in Human History & Prehistory
NOV 10, 2022
Human or Host? Parasites in Human History & Prehistory
We've all seen the latest historical interpretations on television, the movies, or even the stage. And while talented co ...
SEP 19, 2022
Genetics & Genomics
Some Gene Variants May Encourage Active or Sedentary Lifestyles
SEP 19, 2022
Some Gene Variants May Encourage Active or Sedentary Lifestyles
There is still a lot of debate about how much a person's genes influence their behavior. Twin studies are one way to hel ...
SEP 23, 2022
Health & Medicine
Novel Approach Developed for Ear Replacement Surgery
SEP 23, 2022
Novel Approach Developed for Ear Replacement Surgery
In a recent study published in Facial Plastic Surgery & Aesthetic Medicine, a team of researchers have developed a n ...
OCT 07, 2022
Earth & The Environment
United Nations Genetic Diversity Target Deadline Has Passed
OCT 07, 2022
United Nations Genetic Diversity Target Deadline Has Passed
In a recent study published in Science, an international team of researchers led by Stanford University examine how habi ...
OCT 17, 2022
Clinical & Molecular DX
New Study Shows Biological Differences in the Second-Most Common Type of Breast Cancer
OCT 17, 2022
New Study Shows Biological Differences in the Second-Most Common Type of Breast Cancer
Though invasive lobular carcinoma (ILC) is the second-most common type of breast cancer, it has historically been resear ...
NOV 23, 2022
Genetics & Genomics
How Mutant Mitochondrial DNA is Removed
NOV 23, 2022
How Mutant Mitochondrial DNA is Removed
Mitochondria are very special organelles. These cellular powerhouses do more than generate energy. They are known to car ...
Loading Comments...