Cap-specific adenosine methyltransferase that catalyzes formation of N(6,2'-O-dimethyladenosine cap (m6A(m by methylating the adenosine at the second transcribed position of capped mRNAs. Recruited to the early elongation complex of RNA polymerase II (RNAPII via interaction with POLR2A and mediates formation of m6A(m co-transcriptionally.,CAPAM,hCAPAM,hPCIF1,C20orf67,PPP1R121,PCIF1,Epigenetics & Nuclear Signaling,PCIF1