EXPRESSION OF A PLANT GENOME IN HNRNA AND MESSENGER-RNA

Repreaentation of genomic kinetic sequence classes and sequence complexities were investigated in nuclear and polymal RNA of the higher plant Petroselinum.sativuin (paraley). Two different methods indicated that most if not all polyscrial poly(A)-RNA is transcribed from unique sequences.As measured by saturation hybridization in root callus and young leaves 8.7% and 6.2%, respectively, of unique DNA were transcribed in mENA corresponding to 13.700 and 10.000 average sized genes. Unique nuclear DNA hybridized with an excess of polyscanal poly(A)mRNA to the same extent as with total polyscenal ruth. 3H-cDNA - poly(A)mRNA hybridization kinetics revealed the presence of two abundance classes with 9.200 and about 30 different mRNAs in leaves and two abundance classes with 10.500 and 960 different mRNAs in callus cells.The existence of plant poly(A)hnRNA was proven both by its fast kinetics of appearance, its length distribution larger than mRNA, and its sequence complexity a few times that of polysomal RNA. © 1979 Information Retrieval Limited.