Transcriptional activation increases RNA silencing efficiency and stability in the fungus Mucor circinelloides

Initiation and maintenance of the RNA silencing mechanism was investigated after transcriptional activation of the transgene carB in Mucor circinelloides. Light induced transcription of the reporter gene carB specifically increased the 21-nt siRNA compared with the 25-nt siRNA and rose the silencing maintenance from 48% up to 93% of the descendent colonies. In accordance, induced transcription of the gene carB through disruption of the gene crgA increased the initial silencing frequency up to 30-fold, when compared with the frequency of silencing obtained using a crgA+ genetic background.