Transcription factors and evolution: An integral part of gene expression (Review)

Gene expression is a complex process that is essential to living organisms. Gene expression plays the important role of converting information that is encoded in a gene into a functional product. The primary regulators of gene expression are transcription factors (TFs). TFs are proteins that can bind specific DNA sequences and regulate gene expression. Their evolution is influenced by a large number of factors, including epigenetic mechanisms, gene regulatory elements and molecular cofactors. These molecular mediators, along with transcription factors, form a network that governs gene expression. Elucidating the mechanisms through which TFs have evolved and how they influence the evolution of other regulatory molecules can provide information on organism evolution and on the development of phenotypic variations. The aim of this review article was to provide a summary of the current literature on transcription factor evolution, function and how such evolution has played an important role in the emergence of complex organisms.