Cul4 molecule helps to deposit DNA-packaging histone proteins onto DNA, an integral step in cramming yards of genetic code into compact coils that can fit into each cell. The research is published in the issue of the journal Cell. The results explain on a molecular level how Cul4 enables the handoff of histones from the proteins escorting them from their birthplace in the cell to their workplace on the DNA, where they can begin wrapping DNA up into tidy units called nucleosomes.
"We suggest that cancer cells may have evolved a mechanism to disrupt proper nucleosome assembly by altering Cul4 and other factors, which in turn could affect the stability of the genome and promote the formation of tumors," says senior study author Zhiguo Zhang, Ph.D., a molecular biologist at Mayo Clinic.
DNA Finger Printing
DNA fingerprinting is a technique which helps forensic scientists and legal experts solve crimes, identity thefts, legal suits and terrorism cases.
Advertisement
To protect the integrity of the genome, DNA is packaged tightly, first around spools of histone to form nucleosomes, then stacked on top of each other to form chromatin and finally looped and coiled to form chromosomes. Depending on whether and how histones interact with a given genetic sequence, the DNA is either closed up tightly within this package or lies open so that the underlying genes can be read and become active.
Researchers have long known that special proteins -- called histone chaperones -- escort histones around the cell, but how they finally let go of the histones to deposit them onto DNA was unclear.
![Research: Histone-modifying Proteins, Not Histones, Remain Associated With DNA Through Replication]( "Research: Histone-modifying Proteins, Not Histones, Remain Associated With DNA Through Replication")
It's widely accepted that molecular mechanisms mediating epigenetics include DNA methylation and histone modifications.
Dr. Zhang wondered if Cul4, which is altered in a number of human cancers, including breast cancer, squamous cell carcinomas, adrenocortical carcinomas, and malignant mesotheliomas, might be involved. So he and his colleagues developed a series of cellular assays in yeast and in human cells to investigate the role of Cul4 in nucleosome assembly.
They found that Cul4 modifies the chemical entities on the surface of the histones, weakening the interaction between them and the histone chaperones charged with their care. They noticed that the same observations held true in the yeast indicating that the role of Cul4 in nucleosome assembly and genome stability is likely conserved between yeast and human cells.
"We uncovered a novel molecular mechanism whereby Cul4 regulates nucleosome assembly," says Dr. Zhang. "Our finding underscores the fact that proper regulation of the nucleosome assembly pathway is a key step in maintaining genome stability and epigenetic information."
Co-authors of the article are Junhong Hang, Ph.D., Hui Zhang, Zhiquan Wang, Ph.D. and Hui Zhou. The study was funded by the National Institutes of Health grants # GM81838 and GM72719. The Epigenomic Program, Center of Individualized Medicine, Mayo Clinic also partly supported this study.
Source: Newswise
Research: Histone-modifying Proteins, Not Histones, Remain Associated With DNA Through Replication
It's widely accepted that molecular mechanisms mediating epigenetics include DNA methylation and histone modifications.
Advertisement
Dr. Zhang wondered if Cul4, which is altered in a number of human cancers, including breast cancer, squamous cell carcinomas, adrenocortical carcinomas, and malignant mesotheliomas, might be involved. So he and his colleagues developed a series of cellular assays in yeast and in human cells to investigate the role of Cul4 in nucleosome assembly.
They found that Cul4 modifies the chemical entities on the surface of the histones, weakening the interaction between them and the histone chaperones charged with their care. They noticed that the same observations held true in the yeast indicating that the role of Cul4 in nucleosome assembly and genome stability is likely conserved between yeast and human cells.
"We uncovered a novel molecular mechanism whereby Cul4 regulates nucleosome assembly," says Dr. Zhang. "Our finding underscores the fact that proper regulation of the nucleosome assembly pathway is a key step in maintaining genome stability and epigenetic information."
Co-authors of the article are Junhong Hang, Ph.D., Hui Zhang, Zhiquan Wang, Ph.D. and Hui Zhou. The study was funded by the National Institutes of Health grants # GM81838 and GM72719. The Epigenomic Program, Center of Individualized Medicine, Mayo Clinic also partly supported this study.
Source: Newswise
Advertisement
 Next-Generation Genome Sequencing can Help Researchers Find Potential Therapeutic Targets for Patients With Advanced CancersGenomic sequencing can be used to find potential therapeutic targets even for patients with advanced and rapidly transforming cancer according to a joint study. | Advertisement
|
Advertisement
Recommended Reading
Latest Genetics & Stem Cells News
Can stem cell therapy cure fistula? Yes, treatment with stem cells has had a success rate when used in perianal fistulas due to Crohn's Disease.
In zebrafish models of SURF1 mitochondrial disease, scientists have discovered drugs to prevent neurological decompensation.
New study advances intravitreal gene therapy platform to develop safe and effective therapies for visual loss in Usher Syndrome, rare disorder.
The study experiments shed light on a rare example of how autism-associated mutation could altered nuclear dynamics.
A genotype-first approach to patient care involves selecting patients with specific genomic variants and then studying their traits and symptoms.