Synthesis and automated detection of fluorescently labeled primer extension products

Common methods for determination of transcription initiation sites are base d oil the extension of radioactively labeled primers or internal labeling o f extension products with reverse transcriptase. Here, we describe a modifi cation of this procedure, adapted for automated detection of extension prod ucts by using fluorescent primers and an optimized reaction protocol. This facilitates high-throughput screening to detect mRNA start-points of large DNA regions and significant reduces the time required to determine sites of transcription initiation.