EPB41L4A-AS1 long noncoding RNA acts in both cis- and trans-acting transcriptional regulation and controls nucleolar biology

Mammalian genomes are pervasively transcribed into long noncoding RNAs (lncRNAs), whose functions and modes of action remain poorly understood. EPB41L4A-AS1 is an evolutionary conserved and broadly and highly expressed lncRNA that produces the H/ACA snoRNA SNORA13 from one of its introns. We studied the consequences of EPB41L4A-AS1 perturbation in breast cancer cells and found that it acts both in cis to enhance expression of the proximal EPB41L4A gene, and in trans by broadly regulating gene expression, including expression of snoRNAs, transcription of genes involved in nucleolar biology and the distribution of nucleolar proteins. These effects are phenocopied by loss of SUB1, an interactor of EPB41L4A-AS1 and are observed following transient perturbations of EPB41L4A-AS1 that do not affect steady-state SNORA13 levels. Exogenous expression of the full-length EPB41L4A-AS1 locus but not SNORA13 expression can rescue the trans-acting transcriptional effects of its perturbation. The EPB41L4A-AS1 gene is thus a versatile locus producing RNA molecules acting on multiple levels and important for key cellular functions.