Recent Trends in Eukaryotic Transcription: Crucial Role of Gene Architecture in Transcriptional Regulation

Abstract

The Human Genome Project has identified more than 25,000 genes in our cells. Not all of these genes are expressed at the same time or in every cell of our body. A fundamental question in gene expression is how the coordinated expression of genes is achieved during growth, development and homeostasis. The expression of genetic information is regulated to a great extent at the level of transcription. In eukaryotes, RNA polymerase II is the main transcription enzyme, which transcribes protein coding genes and a number of non-coding RNAs. The transcription by RNA polymerase II is regulated by cis-acting DNA elements and trans-acting accessory protein factors. The enhancer, promoter and terminator are the most important DNA elements required for transcription by RNA polymerase II, while accessory protein factors include gene-specific transcription factors, the general transcription factors and termination factors. The generally accepted view is that the factors occupying the promoter region play a dedicated role in initiation of transcription and those operating at the terminator end are exclusively required for the termination step of transcription. The research in my and other laboratories has challenged this dogma.