Manipulation of the human tRNA pool reveals distinct tRNA sets that act in cellular proliferation or cell cycle arrest

Abstract

Different subsets of the tRNA pool in human cells are expressed in different cellular conditions. The ‘proliferation-tRNAs’ are induced upon normal and cancerous cell division, while the ‘differentiation-tRNAs’ are active in non-dividing, differentiated cells. Here we examine the essentiality of the various tRNAs upon cellular growth and arrest. We established a CRISPR-based editing procedure with sgRNAs that each target a tRNA family. We measured tRNA essentiality for cellular growth and found that most proliferation-tRNAs are essential compared to differentiation- tRNAs in rapidly growing cell lines. Yet in more slowly dividing lines, the differentiation-tRNAs were more essential. In addition, we measured the essentiality of each tRNA family upon response to cell cycle arresting signals. Here we detected a more complex behavior with both proliferation-tRNAs and differentiation tRNAs showing various levels of essentiality. These results provide the so-far most comprehensive functional characterization of human tRNAs with intricate roles in various cellular states.

Protein synthesis control in cancer: selectivity and therapeutic targeting

“…Increased levels of initiator methionine tRNA, particularly in stromal fibroblasts, are sufficient to promote tumor invasion, migration, and metastasis, specifically through altered translation of extracellular matrix components and dysregulated integrin signaling (Birch et al , 2016; Clarke et al , 2016). Moreover, cancer‐specific tRNA signatures can be crucial for the fate of the cells as they can coordinate the selective expression of different cellular programs, such as proliferation or differentiation (Gingold et al , 2014; Aharon‐Hefetz et al , 2020). In addition, tumor cells also mistranslate with higher frequency compared to non‐transformed cells and this translational error can promote tumor growth (Santos et al , 2018).…”

A novel role for nucleolin in splice site selection

“…cDNA was synthesized from up to 3 µg of RNA, using dT15 primer. Reverse transcription of ini-tRNA was done using TGIRT-III Enzyme (InGex; 5,073,018) as described [ 77 ], using the RNA-DNA double-strand primers with T overhang described in Supplementary Methods, with the kind advise and help of the laboratory of Dr. Y. Pilpel (Weizmann Institute).…”

Physiological and engineered tRNA aminoacylation

“…tRNA abundance is dependent on cell state and hallmark studies have suggested that tRNAs in human tissues are organized into distinct sets which are used for protein synthesis during cell proliferation or differentiation, respectively (Aharon‐Hefetz et al, 2020; Gingold et al, 2014; Figure 2c). Codons from each defined tRNA pool are used for key genes which define each cell state (Gingold et al, 2014).…”