circTulp4 functions in Alzheimer's disease pathogenesis by regulating its parental gene, Tulp4.

Alzheimer’s disease (AD)—one of the most common neurodegenerative diseases worldwide—impairs cognition, memory, and language ability and causes dementia. However, AD pathogenesis remains poorly elucidated. Recently, a potential link between AD and circular RNAs (circRNAs) has been uncovered, but only a few circRNAs that might be involved in AD have been identified. Here, we systematically investigated circRNAs in the APP/PS1 model mouse brain through deep RNA sequencing. We report that circRNAs are markedly enriched in the brain and that several circRNAs exhibit differential expression between wild-type and APP/PS1 mice. We characterized one abundant circRNA, circTulp4, derived from Intron1 of the gene Tulp4. Our results indicate that circTulp4 predominantly localizes in the nucleus and interacts with U1 small nuclear ribonucleoprotein particle (snRNP) and RNA polymerase II to modulate the transcription of its parental gene, Tulp4, and thereby regulate the function of the nervous system, and might participate in the development of AD.