THE RIBOSOMAL 5.8S RNA AS A TARGET SITE FOR P53 PROTEIN IN CELL-DIFFERENTIATION AND ONCOGENESIS

Previous studies have shown that the ribosomal 5.8S rRNA of human cell s is partially methylated in a tissue-specific fashion, a modification which occurs largely or entirely in the cytoplasm. More recent studie s have shown that the 5.8S rRNA forms a covalent linkage with tumor su ppressor p53 protein and have suggested that this RNA plays a function al role in protein elongation. We now show that the expression of p53 protein in Schizosaccharomyces pombe results in cells which: morpholog ically resemble transformed cells expressing mutant 5.8S rRNA; are equ ally compromised in their ability to sustain protein synthesis, in vit ro; and contain polyribosome profiles which strongly resemble the elev ated profiles which also are observed with mutated 5.8S rRNA. Taken to gether, these results provide new physiological evidence of the possib ility that the 5.8S rRNA is an important target in the control of ribo some function during cell differentiation and oncogenesis. (C) 1997 El sevier Science Ireland Ltd.