| abstract |
The invention pertains to a process for producing a determined polypeptide of interest or repeats thereof in a seed forming plant. It comprises: cultivating plants obtained from regenerated plant cells or from seeds of plants obtained from said regenerated plant cells over one or several generations, whose genetic patrimony, replicable with said plants, comprises a precursor-coding nucleic acid sequence encoding the precursor of a plant storage protein and placed under the control of a seed promoter, said precursor-coding nucleic acid being modified in a non-essential region of its relevant sequence which encodes the mature storage protein or a sub-unit thereof with a nucleic acid insert in appropriate reading phase relationship with the surrounding part of said relevant sequence, said insert including a determined segment encoding a heterologous determined polypeptide of interest or repeats thereof linked to each other and downstream and upstream thereof to the remainder parts of said relevant sequence through codons encoding aminoacid(s) which define selectively cleavable border sites surrounding the peptide of interest in the hybrid storage protein encoded by the so-modified relevant sequence of said precursor-coding nucleic acid; recovering the seeds of the cultivated plants and extracting the hybrid storage proteins contained therein; cleaving out the peptide of interest from said hybrid storage protein, purifying and recovering the peptide of interest. The polypeptide of interest may be a biologically active protein and/or a labeled protein. |