Regulation of human RPS14 transcription by intronic antisense RNAs and ribosomal protein S14

Abstract

RNase protection studies reveal two stable RNAs (250 and 280 nucleotides) transcribed from the antisense strand of the human ribosomal protein gene RPS14's first intron. These transcripts, designated α-250 and α-280, map to overlapping segments of the intron's 5' sequence. Neither RNA encodes a polypeptide sequence, and both are expressed in all human cells and tissues examined. Although α-280 is detected among both the cells' nuclear and cytoplasmic RNAs, the great majority of α-250 is found in the cytoplasmic subcellular compartment. As judged by its resistance to high concentrations of α-amanitin, cell-free transcription of α-250 and α-280 appears to involve RNA polymerase I. Tissue culture transfection and cell-free transcription experiments demonstrate that α-250 and α-280 stimulate S14 mRNA transcription, whereas free ribosomal protein S14 inhibits it. Electrophoretic mobility shift experiments indicate specific binary molecular interactions between r-protein S14, its message and the antisense RNAs. In light of these data, we propose a model for fine regulation of human RPS14 transcription that involves RPS14 intron 1 antisense RNAs as positive effectors and S14 protein as a negative effector.