Fig. 6

Schematic diagram of the possible regulation mechanism of BmCHSA-2b tissue- and stage-specific transcription in silkworm. At larval stage, the methyltransferase BmDnmt1 bound to the CpGI2 of the BmCHSA-2b intragenic promoter and methylated the CpGI2, resulting in the turning-off of the BmCHSA-2b transcription; during the middle pupal stage, BmDeaf1 bound to the unmethylated CpGI2 and suppressed BmDnmt1 binding to the CpGI2 of the BmCHSA-2b intragenic promoter, resulting the inhibition of methylation of the CpGI2 and then the turning-on of the BmCHSA-2b transcription