Gene Is Activated by Its Antisense Long Noncoding RNA.

erythrocyte membrane protein 1, encoded by gene, is an immunodominant antigen mediating immune evasion in humans. At a given time, only a single gene is commonly expressed in one parasite. However, the regulation mechanism of transcription remains largely unknown. In this study, we identified the antisense long non-coding RNA (aslncRNA) derived from intron as an activation factor for the corresponding gene. The exogenous artificial aslncRNA transcribed by T7 RNA polymerase from episome can specifically activate the homologous gene, and the exogenous aslncRNA activates transcription of both mRNA and endogenous aslncRNA in a manner independent of the conserved intron sequence within the gene family. Interestingly, the newly activated gene and the previously dominant gene then could be co-expressed in the same parasite nuclei, which suggests that the aslncRNA-mediated gene activation could escape from the control of mutually exclusively expression of the gene family. Together, our work shows that aslncRNA is the activator responsible for gene transcriptional regulation.