Expression of a chemically synthesized gene for human epidermal growth factor under the control of cauliflower mosaic virus 35S promoter in transgenic tobacco.

Nicotiana tabacum was transformed with a chemically synthesized gene encoding the human epidermal growth factor (hEGF) under control of the CaMV-35S promoter. The hEGF gene sequence was present at one to several copies in the primary transformant plants (R0), and a transcript with the expected length was produced. Slot blot analysis of total RNAs of the progeny (R1) seedlings, originating from self-pollination of the R0 plants, showed that the level of mRNA expression was generally, but not always, heritable. The highest hEGF peptide content per unit of total soluble protein in young (upper) R1 leaves so far examined by an immunological method was about 0.001%. These results suggest that either the hEGF peptide was less stable than the average leaf protein, or the hEGF mRNAs were not efficiently translated.