RNAs specifically affect gene expression in a length, position and sequence dependent manner.

We aim to explore if RNA regulating gene expression is affected by length, sequence and position of RNA. HeLa cells were co-transfected with modulator plasmids (derived from pcDNA3.1 vector containing different length regulating sequences that produce RNAs) and reporter plasmids (derived from pEGFP-C1 vector); In addition, HeLa cells were transfected with plasmids that possess different sequences of downstream or adjacent genes of GFP reporter gene. We found that long inserting sequences of modulator plasmids induced stronger GFP gene activation than short inserting sequences. Changing of downstream sequences of GFP gene induced significant effects on GFP gene expression. Short sequences of adjacent genes of GFP activated GFP gene. Bioinformatics analysis of genes which is highly expressed in differentiating cells (thymocyte cells, germinal center B-cells) and quiescent cells (T cells, B cells) shows that differentiating cells produce longer RNA than quiescent cells. These findings demonstrate that the length, sequence and producing position of RNAs are important factors for RNA regulating gene expression.