Regulation of PHOX2B gene expression by the long non‐coding natural antisense RNA PHOX2B‐AS1

Paired mesoderm homeobox protein 2B (PHOX2B) is a transcription factor essential for autonomic nervous system development. Heterozygous mutations in the PHOX2B gene are associated with neurodevelopmental disorders, including congenital central hypoventilation syndrome and Hirschsprung's disease. Additionally, PHOX2B plays a role in the genetic landscape of neuroblastoma, with mutations detected in both familial and sporadic forms of this rare cancer. Notably, PHOX2B is highly expressed in most neuroblastoma cells. Despite its significance, little is known about the regulation of PHOX2B gene expression, and limited attention has been given to the genomic features of the antisense strand at the PHOX2B locus, although the presence of an antisense transcript is suggested by bioinformatics analyses. In this study, we characterize the recently annotated human antisense transcript PHOX2B-AS1 and the previously unidentified mouse antisense Phox2b transcript. Our findings reveal that PHOX2B positively regulates PHOX2B-AS1 expression and that inhibiting the antisense transcript reduces PHOX2B protein levels. Together, these results provide strong evidence for the existence of a gene antisense to PHOX2B and highlight a strict correlation and reciprocal regulation between PHOX2B and PHOX2B-AS1.