A new paradigm has emerged in recent years characterizing transcription 
initiation as a bidirectional process encompassing a larger proportion of the 
genome than previously thought. Past concepts of coding genes thinly scattered 
among a vast background of transcriptionally inert noncoding DNA have been 
abandoned. A richer picture has taken shape, integrating transcription of coding 
genes, enhancer RNAs (eRNAs), and various other noncoding transcriptional 
events. In this review we give an overview of recent studies detailing the 
mechanisms of RNA polymerase II (RNA Pol II)-based transcriptional initiation 
and discuss the ways in which transcriptional direction is established as well 
as its functional implications.