Diagnostic use of anti-modified nucleoside monoclonal antibody

Pseudouridine as a novel biomarker in prostate cancer

Epitranscriptomic analysis has recently led to the profiling of modified nucleosides in cancer cell biological matrices, helping to elucidate their functional roles in cancer and reigniting interest in exploring their use as potential markers of cancer development and progression. Pseudouridine, one of the most well-known and the most abundant of the RNA nucleotide modifications, is the C5-glycoside isomer of uridine and its distinctive physiochemical properties allows it to perform many essential functions. Pseudouridine functionally (a) confers rigidity to local RNA structure by enhancing RNA stacking, engaging in a cooperative effect on neighboring nucleosides that overall contributes to RNA stabilization (b) refines the structure of tRNAs, which influences their decoding activity (c) facilitates the accuracy of decoding and proofreading during translation and efficiency of peptide bond formation, thus collectively improving the fidelity of protein biosynthesis and (e) dynamically regulates mRNA coding and translation. Biochemical synthesis of pseudouridine is carried out by pseudouridine synthases. In this review we discuss the evidence supporting an association between elevated pseudouridine levels with the incidence and progression of human prostate cancer and the translational significance of the value of this modified nucleotide as a novel biomarker in prostate cancer progression to advanced disease.

NML-mediated rRNA base methylation links ribosomal subunit formation to cell proliferation in a p53-dependent manner

Ribosomal RNAs (rRNAs) act as scaffolds and ribozymes in ribosomes, and these functions are modulated by post-transcriptional modifications. However, the biological role of base methylation, a well-conserved modification of rRNA, is poorly understood. Here, we demonstrate that a nucleolar factor, nucleomethylin (NML; also known as RRP8), is required for the N(1)-methyladenosine (m(1)A) modification in 28S rRNAs of human and mouse cells. NML also contributes to 60S ribosomal subunit formation. Intriguingly, NML depletion increases 60S ribosomal protein L11 (RPL11) levels in the ribosome-free fraction and protein levels of p53 through an RPL11-MDM2 complex, which activates the p53 pathway. Consequently, the growth of NML-depleted cells is suppressed in a p53-dependent manner. These observations reveal a new biological function of rRNA base methylation, which links ribosomal subunit formation to p53-dependent inhibition of cell proliferation in mammalian cells.