Cellular and tissue characteristics are results of dynamic regulation of gene expression. DNA wrapped into proteins, referred to as chromatin, requires involvement of mechanisms guiding accessibility of specific sequences. In higher organisms, chromatin remodeling proteins are indispensable in regulating chromatin structure including ISWI ATPase SMARCA5. SMARCA5 is involved in almost any transaction on DNA including transcription, however precise in vivo role of SMARCA5 in these processes remains unknown. To advance understanding of specific role of SMARCA5 in the development of chromatin structure during transcription we devised cellular model in which SMARAC5 level is manipulated while chromatin structure development and transcriptional response are monitored. Our data indicate that the transfected DNA template that is transcribed is enriched with histone H3 and its specific methylation of Histone H3 lysine (K) 4, a mark of active chromatin structure. Overexpression of SMARCA5 results within the reporter gene coding sequence in ~2,5-3 fold increase of both H3 occupancy an its modification H3K4Me3. Increased DNA template commitment into chromatinization is associated with repression of reporter gene expression. These results are supported by studies indicating dynamic development of nucleosomal...

The chromatin structure, consisting of DNA and histones, changes dynamically during the cell cycle and cell differentiation. DNA can only be transcribed and replicated when it is packaged loosely, whereas tight packaging allows for more efficient storage. Chromatin remodelling is therefore one of the tools of gene expression control. The chromatin remodelling factors recognise chromatin with varying specificity and have an effect on the interaction between DNA and the histones. One of these factors is the Smarca5 protein. This study investigates the role of Smarca5; its goal is to create a mouse model with the ability to trigger Smarca5 overproduction in specific tissues. This model will be used to study the effect of a high, unregulated dose of Smarca5 on the physiological function of the protein. Previous studies have shown that non-physiological expression of a chromatin-remodelling factor can lead to malignant transformation. Our model can help to understand this process. Another goal of this study is to investigate some phenotype aspects of the mouse model with conditional deletion of Smarca5 in T and B cells, in particular the effects of this deletion on progenitor cell differentiation. Our results show that Smarca5 has an important role in lymphocyte development, and we have observed that...