ABSTRACT
As a rule proteins can be divided into two: constitutive synthesized by cells in fixed amounts, independent of need, and inducible or repressible whose synthesis is dependent on the regulatory mechanisms of adequate genes. The role of chromatin structure in regulation of gene expression is experimentation with specific genes introduced into other cells. The regulatory genes make some kind of switching mechanism which turns on and off a whole set of structural genes of the given operon. Complementary sequences of the transcripts may form secondary structures, and thus influence termination of transcription. In this way translation of the leader sequences may determine transcription. Self-generated control model products of gene expression may play the role of inducers or repressors. There also may exist negative or positive mechanisms of gene expression. Deoxyribonucleic acid (DNA) supercoiling also seems to be relevant for gene expression.
