Try looking at the paper by Melton et al for some tips on how to increase yields of in vitro transcripts. It is NAR 12, 7035-56. Good luck. -- Frances Hannan BILMS, Zoology, Downing St, Cambridge, CB2 3EJ, UK Phone (0223)336663, FAX (0223)461954 flh at mole.bio.cam.ac.uk