Testing DNA conformation with AO by confocal and epifluorescence microscopy: (A, B).

The study of human cells conducted by the University of Latvia researchers in collaboration with the Latvian Biomedical Research and Study Centre and Riga Technical University have resulted in finding an unusual DNA form that differs by its nuclear envelope and genome function. The study helps to understand the process of cancer cell development and to find treatments for certain forms of cancer.

“The nucleus is like a library containing bookshelves; each book is one gene. If the library undergoes repairs, most of the shelves with less-read books can be pushed together in one corner to free a half of the library where the ceiling could be painted. The books stacked in one corner are not available, consequently, these genes are not available. They are somehow packaged,” – thus Dr. biol., assoc. prof. Tūrs Selga begins to describe the topic of the study. The study revealed that DNA chromosomes are enveloped or covered by another type of DNA, whose molecule differs chemically. Those are DNA of A and B form. This special enveloping is helpful for cells when DNA is “packaged” – this enables to “pack” also the damaged DNA fragments. “The damaged DNA fragments packed in this way can be transferred to cell lysosomes and degraded to prevent interference with the rest of the cytoplasm," explains T. Selga. The microscopy with a confocal laser scanning microscope was performed during this study at the University of Latvia. This microscopy is a means of spatial imaging. “I'll return to the example of the library. We need to understand and prove that the books are stacked in one corner and the film is laid over the shelves. In the same way, we were able to distinguish these two forms of DNA by a special dyeing method, and distinguishing was simple – the A form dyes green, B dyes red. Then we studied, what is covered with what, where each was located and what was changing,” illustrates T. Selga. A fundamental understanding of universal nuclear architecture and DNA envelope provides valuable additional information on new forms of cancer treatment. “Cancer is a very treacherous term. In any case, it is an uncontrolled cell division, but the problem is that, depending on the cells wherein the cancer originates, it manifests itself in very different ways. Skin melanoma is not the same as lung cancer. They are very different and need to be treated differently,” says associate professor. This study helps to explain why radiation therapy does not always help to treat cancer, it lacks therapeutic effect. Associate professor believes that certain protein genes and gene therapies should be selected for the development of new cancer therapies, thereby enabling to specifically treat cancer types or forms of other diseases. However, further fundamental research is required for this purpose. This research has been acknowledged as one of the most significant accomplishments in 2018 and will receive the Annual Scientific Achievement Recognition Award of the Latvian Academy of Sciences. The study was implemented by Dr. biol. Kristīne Salmiņa, full member of LAS, Dr. habil. med. Jekaterina Ērenpreisa, Dr. biol. Tālivaldis Freivalds, Dr. biol. Tūrs Selga, Mg. Germanis Sorokins, Jēkabs Krīgerts (master’s programme student). Read the publication HERE.

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