Vol 58, No 3 (2024)

SINEs are mobile genetic elements of multicellular eukaryotes that arose during evolution from various tRNAs, as well as from 5S rRNA and 7SL RNA. Like the genes of these RNAs, SINEs are transcribed by RNA polymerase III. Transcripts of some mammalian SINEs have the ability to AAUAA-dependent polyadenylation that is unique for transcriptions generated by RNA polymerase III. Despite a certain similarity with canonical polyadenylation of mRNAs (transcripts of RNA polymerase II), these processes apparently differ significantly. The purpose of this work is to evaluate how important for polyadenylation of SINE transcripts are proteins of the CPSF complex formed by mPSF and mCF subcomplexes which directs mRNA polyadenylation. In HeLa cells, siRNA knockdowns of the CPSF components were carried out, after which the cells were transfected with plasmid constructs containing SINEs. A decrease of polyadenylation of the SINE transcripts as a result of the knockdown of the proteins was evaluated by Northern-hybridization. It turned out that the CPSF components, such as WDR33 and CPSF30, contributed to the polyadenylation of SINE transcriptions, while the knockdown of CPSF100, CPSF73 and symplekin did not reduce the polyadenylation of these transcripts. Wdr33 and CPSF30, along with the CPSF160 and Fip1 previously studied, are components of the subcomplex mPSF responsible for mRNA polyadenylation. Thus, the available data suggest the importance of all mPSF proteins for SINE transcriptions. At the same time, the CPSF100, CPSF73, and symplekin, forming the subcomplex mCF, are responsible for the cleavage of pre-mRNA, therefore, their non-participation in the polyadenylation of SINE transcriptions seems quite natural.

ArdA are DNA-mimic proteins which inhibit type I restriction-modification (RMI) systems by binding to them instead of DNA. The question of specificity to DNA methylation sites recognized by RMI complexes remains to be answered: is ArdA able to mimic a specific DNA site? In this work, we cloned ardA genes from three Gram-positive bacteria Agrobacterium tumefaciens, Pseudomonas monteilii and Xanthomonas sp. Antirestriction abilities of these genes were tested against three RMI systems of Escherichia coli, differing in DNA recognition/methylation sites. It was shown that despite the similarity of predicted structures of the studied ArdA proteins, they have significant specificity for three RMI systems. The results obtained may indicate the ability of DNA-mimetics to imitate specific DNA sites.

Using a computer modelling approach we proposed the structure of a potential GC-specific DNA ligand, which could form a complex with DNA in the minor groove similar to that formed by Hoechst 33258 at DNA AT-enriched sites. According to this model MBoz₂A, a bisbenzoxazole ligand, was synthesized. The results of spectrophotometric methods supported the complex formation of the compound under study with DNA differed in the nucleotide composition.

Long non-coding RNAs (lncRNAs) are involved in many cellular processes while displaying high tissue specificity. In contrast, protein-coding genes, including the category of housekeeping ones, exhibit broad expression patterns. The aim of this study was to highlight the functional importance of widely expressed lncRNAs. We analyzed experimental data from cell-growth screen of lncRNA loci in human cells, which allowed us to identify 18 lncRNA hits. Notably, these lncRNAs were not only widely expressed in most human tissues, but also played functional roles within them. Detail investigation revealed them encompass a variety of molecular functions, from cardiomyocyte damage controlling to macrophage class switching. Interestingly, experimental data highlighted the fact that a significant part of these lncRNAs encoded small but functional polypeptides. A set of lncRNAs, NEAT1, SNHG1, SNHG7, SNHG12, SNHG15, SNHG16, MIR17HG, LINC00680, LINC00263 and LINC00339, that were highly likely to be translated into small polypeptides was identified. Additionally, for EPB41L4A-AS1, CRNDE, SNHG6, LINC00493, and LINC01420, a dual function associated with both the RNA sequences and small proteins they encoded was established.