WTAP and Alzheimer disease: Consistently, immunoblot analysis demonstrated significant reduction in the protein levels of many of these m6A regulators in the brain cortical tissues from AD patients compared to that from age-matched control patients (Fig. 2 C,D): the m6A writers, including METTL3, METTL14 and WTAP, were significantly reduced by 66.7, 74.0, and 76.0% in AD, respectively.