Before revision:  The theoretically calculated noise expression of proteins shows excellent agreement with an experimental results. 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:  The theoretically calculated noise expression of proteins shows excellent agreement with an experimental result. 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.