The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 system is a revolutionary tool for precise genome editing across various cell types. Ribonucleoproteins (RNPs), encompassing the Cas9 protein and guide RNA (gRNA), have emerged as a promising technique due to their increased specificity and reduced off-target effects. This method eliminates the need for plasmid DNA introduction, thereby preventing potential integration of foreign DNA into the target cell genome. Given the requirement for large quantities of highly purified protein in various Cas9 studies, we present an efficient and simple method for the preparation of recombinant Streptococcus pyogenes Cas9 (SpCas9) protein. This method leverages the Small Ubiquitin Like Modifier(SUMO) tag system, which includes metal-affinity chromatography followed by anion-exchange chromatography purification. Furthermore, we compare two methods of CRISPR-Cas9 system delivery into cells: transfection with plasmid DNA encoding the CRISPR-Cas9 system and RNP transfection with the Cas9-gRNA complex. We estimate the efficiency of genomic editing and protein lifespan post-transfection. Intriguingly, we found that RNP treatment of cells, even in the absence of a transfection system, is a relatively efficient method for RNP delivery into cell culture. This discovery is particularly promising as it can significantly reduce cytotoxicity, which is crucial for certain cell cultures such as induced pluripotent stem cells (iPSCs).

Nucleolus-oriented protein nucleolin plays a significant role in the life of a normal mammalian cell. However, nucleolin is also actively expressed in cells of malignant tumors. At the same time, its expression in different types of cancer is significantly increased compared with normal cells. It is interesting that nucleolin localization often varies in tumor cells, namely in the cytoplasm and on the cell membrane. This fact is considered to be a poor prognostic indicator. This work is devoted to the study of the distribution of nucleolin in human glioblastoma cells. Glioblastoma is one of the most aggressive malignant tumors with an absolutely unfavorable prognosis. These tumors have a high proliferative potential, but in addition they are often characterized by invasive properties. Research on lineage cells does not let to fully study these properties of glioblastoma, since lineage cells are very different from the actual tumor. In our study, we used two primary cell cultures of human glioblastoma with varying degrees of invasiveness of the original tumors. The main interest was directed at studying the localization of nucleolin and its correlation with the invariability of the N- and C-termini of the corresponding protein. Particular attention was paid to the significance of the unaltered C-terminus of nucleolin for its distribution in the cells of transplanted human glioblastoma cultures derived from patient tissues. The aim of this work is to find the relationship between the deformation of the N- or C-terminal sequences of nucleolin and its localization.We showed that in glioblastoma cells, with a high degree of invasion, nucleolin is found in the cytoplasm and close to the cell membrane, and the distribution of nucleolin with undeformed C and N-terminal does not match.

Maturing of a messenger RNA (mRNA) is a multi-way process producing mRNA variants through diverse splicing events, alternative polyadenylation, RNA editing, etc. Studying posttranscriptional processing of human cold-inducible RNA binding protein (CIRBP), we discovered yet another mechanism that could be added to this list. We named it excising, and it consists of low-accuracy post-splicing deletion of sequence regions of variable length. The main features of the excising process and putative members of corresponding multiprotein machinery were described with a series of cloning vectors and RNA-pulldown assay. Our results highlight a possible role of U-rich stretches and the proteins targeting such motifs in the discovered process. The discovered mechanism suggests the potential translation of 3’-untranslated regions, which may be an adjuvant way of CIRBP activity inhibition or generation of structural and functional diversity.