Untwisting DNA Reveals New Force that Shapes Genomes

 

    Advanced microscope technology has allowed for the tertiary structure of DNA strands to better be understood and allowed for scientists to visualize how the genome organizes into these 3D structures. This new machinery uses high power lasers alongside chemical conditions that track fluorescent molecules to provide 10 times higher resolution than conventional microscopy. Prior to this new microscope technology it was not possible to analyze the tertiary structures of DNA closely. The new microscopes helped scientists draw correlations between the specific way DNA is transcribed and how it supercoils to form tertiary structures. Transcription was found to generate a force that moves across DNA strands like ripples through water. This is due to structural proteins known as cohesions that "surf" across DNA strands changing the shape of the genome in the process. Researchers believe that the discovery of the way cohesions affect the structure of DNA can help understand more about genetic and developmental disorders as it may be possible to draw correlations between diseases and tertiary structure folds. As DNA is condensed within a cell it forms many loops and coils which cause different sections of the DNA to interact with one another, allowing for individual cells to switch different information on and off. This new advancement shows that transcription aids in the process of determining which parts of the DNA fold to interact with each other. Until recently scientists were only able to predict where tertiary DNA loops were located but not their shape or what caused the coiling to form. The possibilities for this advanced form of microscopy are still being discovered.

Article Link: https://www.sciencedaily.com/releases/2021/07/210722113007.htm

Related Link:   https://www.ncbi.nlm.nih.gov/books/NBK26880/

 

Protein Lattice of Immature HIV Photographed

For the first time ever Scientists have been able to photograph the protein lattice of an immature HIV strand. Researches from the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, along with partners from Heidelberg University combined their efforts to capture the image at an astonishingly high resolution. The Researches collaborate on a joint partnership in the Molecular Medicine Partnership Unit. To their amazement, the building blocks of the immature HIV strand are arranged in a way they did not expect.

             "We assumed that retroviruses like HIV and Mason-Pfizer Monkey Virus would have similar structures, because they use such similar building blocks, but it turns out that their immature forms are surprisingly different from each other. At this point, we don't really know why." – John Briggs, Group Leader & Senior Scientists -EMBL

Immature HIV(center) clearly arranged differently in comparison to the Mason-Pfizer Monkey Virus(left).
 Further rearrangement allows immature HIV to take shape of mature HIV(right).

The scientists used cryo-electron microscopy to study the structure of the protein that surrounded HIV’s genetic material.  Once HIV enters our body it attacks a cell in our immune system. From there, HIV replicates and through assembly, becomes an immature form like the one scientists photographed.

Researchers at the EMBL have photographed an immature strand of HIV before in the early 1990s. However, after two decades, the scientists were able to obtain a detailed picture of the protein lattice that surrounds the immature HIV. With the new image, the scientists can pinpoint exactly where each building block resides in the structure. This allows for potential new drug targets and also provides new details on how potential mutations may affect the replication process.

The new images is a step in the right direction for finding a cure for HIV. As scientists continue their research they’ll hopefully develop new drugs to target particular building blocks in order to diminish the ability for HIV to replicate. Also, this opens the door for research on other viruses. With the clarity of the image, other viruses can be photographed to see how they work in transporting material inside susceptible immune system cells. They may be able to develop new treatment plans to target the transporting of the material into the cells or the force a mutation of the protein replication process in order to defeat HIV and other viruses for good. 

Article: http://www.sciencedaily.com/releases/2014/11/141103082514.htm

Article Related: Cryo-Electron Microscopy - http://www.medicinenet.com/script/main/art.asp?articlekey=24623