AUTHOR=Jing Qingqing , Cao Long , Zhang Liangliang , Cheng Xiu , Gilbert Nicolas , Dai Xueyu , Sun Maoxin , Liang Shaohui , Jiang Lubin 

TITLE=Plasmodium falciparumvar Gene Is Activated by Its Antisense Long Noncoding RNA

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.03117

DOI=10.3389/fmicb.2018.03117

ISSN=1664-302X

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