Genomic deletion by CRISPR/Cas9 reveals a critical role for Evx1as/Evx1 locus in regulating embryonic stem cell differentiation

We report that head to head long noncoding RNAs contribute to transcription and developmental process. Thousands of lncRNAs have been identified in the whole genome, and classified to several subgroups based on the genome position with their coding neighbors. XH, the head to head subgroup is associated with transcription and development in GO analysis. Here, we deleted the promoter and exon1 region which shared by Evx1as/Evx1 XH pair in embryonic stem cells by two sgRNAs-mediated CRISPR. Two homozygous mutants came out from 46 single clones with high efficiency, while two control clones were picked from cells which were only Cas9 transfected. These two mutants failed to activate Evx1 in -LIF differentiation compared to control cells, while Evx1as still have 30% mRNA residual. Meanwhile, we characterized gene expression level among different stages of ESC differentiation and found many differentiated related makers exhibited aberrant regulation, especially endodermal genes. We propose that XH lncRNA and its coding neighbor could regulate each other, and function as a unit to promote ESC differentiation and biological development.