Use of Tissue-Plasminogen Activator as a Reporter Gene

Throughout the past six or seven years, our ability to study and understand the process of eukaryotic gene expression has been greatly enhanced by the use of reporter genes. In essence, a reporter gene encodes a protein product for which a sensitive and convenient assay is available. Transcription of the reporter is driven by the control sequences of interest, so that the level of reporter protein reflects the transcriptional activity, Reporter genes in present usage include the chloramphenicol acetyltransferase (CAT) (ref. 1 ; see elsewhere in this vol) �-galactosidase (�-gal) (ref. 2 ) and, more recently, luciferase genes (see elsewhere in this vol).