An endogenous RNA-synthesis-promoting oligopeptide from Cucurbita pepto var. patissonina.

The effect of CPPTI (Cucurbita pepo patissonina trypsin inhibitor) on the growth of Cucurbita pepo var patissonina (White bush) was examined. Plants treated with CPPTI grew faster than untreated plants and similarly to those treated with gibberellic acid. Isolated cell nuclei from plants treated with CPPTI showed that of the three DNA-dependent RNA polymerases assayed, RNA polymerase I (EC2.7.7.6) activity was preferentially elevated.