You learned in your high school biology class that genes are copied, or transcribed, and that the transcript was used by the ribosome to synthesize a protein. But how does the cell know which genes to transcribe, which form of the gene to use, and when to transcribe it? These questions are answered by various mechanisms collectively referred to as gene regulation. The DNA region upstream of a gene may have various molecules and proteins attached which influence its expression, that DNA region and the histone proteins about which it is wrapped may have methyl groups or other small groups attached to them serving as signals, once transcribed the resulting mRNA transcript may be spliced into alternate forms, the mRNA transcript can also be controlled by snippets of RNA that bind to the transcript, the speed with which the transcript is translated into a protein can be controlled at the ribosome, and so forth. It is an incredible network of signals and mechanisms controlling which genes are used, how they are used, and when they are used. Now, new research is helping to elucidate yet another mechanism which is the equivalent of a fine-control knob on the timing of the transcription process. Read more