Stability of mRNA and proteins of the MRPS18 family in vitro

Aim. The MRPS18 family (MRPS18-1-3) consists of proteins that are the building blocks of the small subunit of the mitochondrial ribosome. Besides, MRPS18-2 exhibit extra-ribosomal functions, taking a part in the cell cycle control, apoptosis, epithelial-mesenchymal transition, and maintenance of pluripotency. There are no data on mRNA stability of MRPS18 family genes. We wanted to examine the stability of mRNA of MRPS18 family genes (MRPS18-1-3) and their protein products in vitro. Methods. The mRNA degradation was assessed upon treatment in cells of breast carcinoma MCF7 and rhabdomyosarcomas TE671 with actinomycin D by a quantitative PCR (qPCR). Proteasomal degradation of proteins were studied in vitro, using pGEM constructs and T7/SP6 Coupled Wheat Germ Extract System. Results. The MRPS18-2 mRNA was characterized by the lowest stability among the analysed transcripts in MCF7 cells, on the contrary to the MRPS18-2 protein that showed a high stability. mRNA of MRPS18-1 and MRPS18-3 demonstrated the higher stability, while these proteins degraded with the higher rate. Conclusions. More should be done to understand how mRNA and protein stability influence the MRPS18-2 protein functions.