Promoters are sequences of DNA that tell RNA polymerase and transcription factors to bond to the DNA and begin transcription.
A promoter is an area of DNA where transcription of the DNA begins. The promoter controls the expression of the gene by signaling to RNA polymerase to begin transcription and the direction in which the polymerase should transcribe the DNA.
Genes express themselves by forming proteins .
Through Transcription , the information of gene is carried onto the mRNA which on Translation produces proteins. This protein can be Structural , or Enzyme or Hormone and thus the gene expresses itself.