Research Articles

Heterogeneous nuclear ribonucleoproteins: role in RNA splicing

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Science  28 Mar 1986:
Vol. 231, Issue 4745, pp. 1534-1539
DOI: 10.1126/science.3952495


Splicing in vitro of a messenger RNA (mRNA) precursor (pre-mRNA) is inhibited by a monoclonal antibody to the C proteins (anti-C) of the heterogeneous nuclear RNA (hnRNA)-ribonucleoprotein (hnRNP) particles. This antibody, 4F4, inhibits an early step of the reaction: cleavage at the 3' end of the upstream exon and the formation of the intron lariat. In contrast, boiled 4F4, or a different monoclonal antibody (designated 2B12) to the C proteins, or antibodies to other hnRNP proteins (120 and 68 kilodaltons) and nonimmune mouse antibodies have no inhibitory effect. The 4F4 antibody does not prevent the adenosine triphosphate-dependent formation of a 60S splicing complex (spliceosome). Furthermore, the 60S splicing complex contains C proteins, and it can be immunoprecipitated with 4F4. Depletion of C proteins from the splicing extract by immunoadsorption with either of the two monoclonal antibodies to the C proteins (4F4 or 2B12) results in the loss of splicing activity, whereas mock-depletion with nonimmune mouse antibodies bodies has no effect. A 60S splicing complex does not form in a C protein-depleted nuclear extract. These results indicate an essential role for proteins of the hnRNP complex in the splicing of mRNA precursors.

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