To understand how cells communicate, the most desirable condition is to monitor them while in their natural state surrounded by other cells as in the tissue. To accomplish this, reporters are needed with signals that can be read from living cells. Although protein reporters have been used for many years, they have the major disadvantage that they provide a signal that is delayed many hours after the gene is activated. RNA aptamers can fold to their active forms inside cells and are a good option as components of reporters that give an immediate signal of transcription.