After the host cell is infected, HPV16 early promoter is activated and a polycistronic primary RNA containing all six early ORFs is transcribed. This polycistronic RNA contains three exons and two introns and undergoes active RNA splicing to generate multiple isoforms of mRNAs.[1] One of the spliced isoform RNAs, E6*I, serves as an E7 mRNA to translate E7 oncoprotein.[50] In contrast, an intron in the E6 ORF that remains intact without splicing is necessary for translation of E6 oncoprotein.[50] However, viral early transcription subjects to viral E2 regulation and high E2 levels repress the transcription.