[Human ribosomal protein S16 inhibites excision of the first intron from its own]

Abstract

Recombinant human ribosomal protein S16 (rpS16) is shown to bind specifically to a fragment of its own pre-mRNA that includes exons 1 and 2, intron 1, and part of intron 2, and to inhibit the splicing of the fragment in vitro. The weaker binding of other recombinant human ribosomal proteins, S10 and S13, to this pre-mRNA fragment indicated that the binding of rpS16 was specific. Besides, poly(AU) and rpS16 mRNA fragment affected poorly the binding of rpS16 to its pre-mRNA, providing another evidence that the interaction was specific. RpS16 specifically inhibited the pre-mRNA fragment splicing whereas recombinant rpS10 and rpS16 did not affect excision of intron from this pre-mRNA fragment in contrast to rpS16. Those positions in rpS16 pre-mRNA fragment that were protected by rpS16 against cleavage by RNases T1, T2 and V1 were found to be located closely to the branch point and 3' splice site in the pre-mRNA. Results obtained support the possibility of the autoregulation of rpS13 pre-mRNA splicing through feedback mechanism.