Question

What is the regulatory gene, or the regulatory elements in an operon?

Answer 1

A gene consists of a transcriptional region and a regulatory region. The transcriptional region is the part of DNA to be transcribed into a primary transcript (an RNA molecule complementary to the transcriptional region). The regulatory region can be divided into cis-regulatory (or cis-acting) elements and trans-regulatory (or trans-acting) elements. The cis-regulatory elements are the binding sites of transcription factors which are the proteins that, upon binding with cis-regulatory elements, can affect (either enhance or repress) transcription. The trans-regulatory elements are the DNA sequences that encode transcription factors.