AUTHOR=Pérez-Molina Rosario , Arzate-Mejía Rodrigo G. , Ayala-Ortega Erandi , Guerrero Georgina , Meier Karin , Suaste-Olmos Fernando , Recillas-Targa Félix 

TITLE=An Intronic Alu Element Attenuates the Transcription of a Long Non-coding RNA in Human Cell Lines

JOURNAL=Frontiers in Genetics

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2020.00928

DOI=10.3389/fgene.2020.00928

ISSN=1664-8021

ABSTRACT=<p><italic>Alu</italic> elements are primate-specific repeats and represent the most abundant type of transposable elements (TE) in the human genome. Genome-wide analysis of the enrichment of histone post-translational modifications suggests that human <italic>Alu</italic> sequences could function as transcriptional enhancers; however, no functional experiments have evaluated the role of <italic>Alu</italic> sequences in the control of transcription <italic>in situ</italic>. The present study analyses the regulatory activity of a human <italic>Alu</italic> sequence from the <italic>AluSx</italic> family located in the second intron of the long intergenic non-coding RNA <italic>Linc00441</italic>, found in divergent orientation to the <italic>RB1</italic> gene. We observed that the <italic>Alu</italic> sequence acts as an enhancer element based on reporter gene assays while CRISPR-Cas9 deletions of the <italic>Alu</italic> sequence in K562 cells resulted in a marked transcriptional upregulation of <italic>Linc00441</italic> and a decrease in proliferation. Our results suggest that an intragenic <italic>Alu</italic> sequence with enhancer activity can act as a transcriptional attenuator of its host lincRNA.</p>