Before revision:  Then, we show that the noise in mRNA level can be sub-Poissonian due to the reinitiation of transcription by RNAP and the mean mRNA level can be increased without increasing the noise  .
After revision:  Then, we show that the noise in mRNA level can be sub-Poissonian due to the reinitiation of transcription by RNAP and the mean mRNA level can be increased without increasing the noise . We find that the reinitiation of transcription behaves like the fine-tuned control process to regulate the mRNA/protein level in the cell .