RNA processing is vital for the high fidelity and diversity of eukaryotic 
transcriptomes and the encoded proteomes. However, control of RNA processing is 
not fully established. Σ RNA is a class of conserved large non-coding RNAs 
(murine Hepcarcin; human MALAT-1) up-regulated in carcinomas. Using antisense 
technology, we identified that RNA post-transcriptional modification is the most 
significant global function of Σ RNA. Specifically, processing of the pre-mRNAs 
of genes including Tissue Factor and Endoglin was altered by hydrolysis of Σ 
RNA/MALAT-1. These results support the hypothesis that Σ RNA/MALAT-1 is a 
regulatory molecule exerting roles in RNA post-transcriptional modification.