[The Structure, Expression, and Non-Canonical Functions of Human rDNA: The Role of Non-Coding Regions].

The genes coding for the rRNAs seem evolutionary conserved on the first glance, but astonish one with their variability in the structure and a variety of functions on closer examination. The non-coding parts of rDNA contain regulatory elements, protein binding sites, pseudogenes, repetitive sequences, and microRNA genes. Ribosomal intergenic spacers are not only in charge with the nucleolus morphology and functioning, namely, the rRNA expression and ribosome biogenesis, but also control nuclear chromatin formation thus mediating cell differentiation. The alterations in the expression of these non-coding regions of rDNA in response to environmental stimuli underlie the keen sense of a cell to various types of stressors. Malfunctioning of this process may result in a wide range of pathologies from oncology to neurodegenerative disease and mental illness. Here, we observe to-date materials on the structure and transcription of the ribosomal intergenic spacer in humans and its role in rRNA expression, in-born disease development, and cancer.

IMMUNOHISTOCHEMICAL STUDY OF DEPIGMENTED SKIN OF VITILIGO PATIENTS.

Immunohistochemical analysis was used to study depigmented skin areas such as macular of depigmentation and skin perimakular areas in vitiligo patients. It has been shown that the cells containing melanocytic cell marker TRP1 are localized both in macular and perimakular areas. Within the macula of depigmentation all TRP1 positive cells are in close contact with the basement membrane. In perimakular areas many cells that have lost contact with the basement membrane, were localized deep in the epidermis. About 92 % of TRP1 positive perimakular cells were also vimentin positive. Vimentin positive cells were numerous in perimakular areas but missing in the macula of depigmentation. Dense groups of cells immunopositive for transcription factor Snail, known as inductor of epithelial-mesenchymal transition, were localized in perimakular areas in close proximity to the macula depigmentation border. Such cells were extremely rare within the macula of depigmentation. There is reason to assume that an intensive process, which is similar to the epithelial-mesenchymal transition, might be the cause of melanocyte death in perimakular field, and thus prevents repigmentation of depigmented areas.

Connection between Proliferation Rate and Temozolomide Sensitivity of Primary Glioblastoma Cell Culture and Expression of YB-1 and LRP/MVP.

Glioblastomas (GBL) are the most common and aggressive brain tumors. They are distinguished by high resistance to radiation and chemotherapy. To find novel approaches for GBL classification, we obtained 16 primary GBL cell cultures and tested them with real-time PCR for mRNA expression of several genes (YB-1, MGMT, MELK, MVP, MDR1, BCRP) involved in controlling cell proliferation and drug resistance. The primary GBL cultures differed in terms of proliferation rate, wherein a group of GBL cell cultures with low proliferation rate demonstrated higher resistance to temozolomide. We found that GBL primary cell cultures characterized by high proliferation rate and lower resistance to temozolomide expressed higher mRNA level of the YB-1 and MDR1 genes, whereas upregulated expression of MVP/LRP mRNA was a marker in the group of GBL with low proliferation rate and high resistance. A moderate correlation between expression of YB-1 and MELK as well as YB-1 and MDR1 was found. In the case of YB-1 and MGMT expression, no correlation was found. A significant negative correlation was revealed between mRNA expression of MVP/LRP and MELK, MDR1, and BCRP. No correlation in expression of YB-1 and MVP/LRP genes was observed. It seems that mRNA expression of YB-1 and MVP/LRP may serve as a marker for GBL cell cultures belonging to distinct groups, each of which is characterized by a unique pattern of gene activity.