Gene-transcription machinery seen poised for action, held in check until needed

For some time, scientists have been tracking down the sequence of biochemical steps required to attract and assemble at the head end of a gene the molecular machinery needed to transcribe that gene to put to work the information it encodes. Now, a new study led by researchers at The Wistar Institute suggests that the gene-transcription machinery, once in place, can remain poised for action but held in check until a triggering signal sends it on its way down the linear DNA molecule.