Illumination of the possible regulation of microRNA miR-124-3P on P60-katanin expression

Katanin, which belongs to the ATPase family, is a microtubule-severing protein and consistings of two subunits. P60-Katanin subunit is expressed by the KATNA1 gene, and the other subunit, p80-katanin, is expressed by the KATNB1 gene. Microtubule severing, which allows its reorganization, is one of the mechanisms performed by microtubule-severing enzymes in line with cellular needs. While the reorganization of microtubules in dividing cells is associated with mitosis, it takes part in the formation of structures such as axons and dendrites, namely 'neuronal branching' in post-mitotic neurons that have lost their division ability. Both subunits of katanin coexist in the cell. Due to the ATPase unit it has, P60-Katanin is involved in severing microtubules, while the regulation of P60-Katanin and ensuring its localization in the centrosome is the major role of the P80-Katanin subunit. Katanin, which has vital functions in the cell, has almost no known regulators. MicroRNAs (miRNA) are a group of non-coding small ribonucleotides which is known to have a very important role in the post-transcriptional regulation of gene expression. Despite this importance of microRNAs in gene regulation, not a single miRNA has yet been experimentally associated with katanin regulation. Within the scope of the thesis study, for the first time in the literature, the effects of miR-124-3p, which was detected by bioinformatics analysis, on the expression of the KATNA1 gene were investigated. For this aim, SH-SY5Y neuroblastoma cells were transfected with pre-miR-124-3p mimic and pre-miR miRNA precursor negative control. Then, qRT-PCR and western blotting methods were used to quantify the effects of this transfection on P60-Katanin expression at both the RNA and protein levels, respectively. The results of this in vitro study showed for the first time that miR-124-3p, which was predicted to bind to KATNA1 mRNA by bioinformatics analysis, may be involved in the regulation of KATNA1 gene expression. The data obtained within the scope of the thesis study will make a significant contribution to the literature for a better understanding of the expressional regulation of P60-Katanin and will also lead the studies to better examine this interaction. Keywords: miR-124-3p, microtubule, P60-Katanin, gene regulation