TULP4 and Alzheimer disease: Through bioinformatics analysis, chromatin isolation by RNA purification, rapid prediction of RNA-protein interactions, and chromatin immunoprecipitation, it was found that circTulp4 mainly localizes in the nucleus and interacts with U1 small nuclear ribonucleoprotein (U1 snRNP) and RNA polymerase II to regulate the transcription of its parent gene Tulp4, which regulates neuronal growth and differentiation, thereby affecting the function of the nervous system and AD development [37].