Question

Give an account of Britten-Davidsons model of regulation of gene activity in eukaryotes.

Answer 1

According to the Britten Davidson model, specific sensor genes represent sequence-specific binding sites (similar to CAP-cAMP binding site in the E. coil) that respond to a specific signal. When sensor genes receive the appropriate signals, they activate the transcription of the adjacent integrator genes. The integrator gene products will then interact in a sequence-specific manner with receptor genes.

A set of structural genes controlled by one sensor site is termed as a battery. Sometimes when major changes are needed, it is necessary to activate several sets of genes. If one sensor site is associated with several integrators, it may cause transcription of all integrators simultaneously thus causing transcription of several producer genes, through receptor sites.

The repetition of integrator genes and receptor sites is consistent with the reports that state that sufficient repeated DNA occurs in the eukaryotic cells. It provides a plausible reason for the observed pattern of interspersion of moderately repetitive DNA sequences and single-copy DNA sequence.