Abstract: Sedoheptulose-1,7-bisphosphatase (SBPase) is a key enzyme in the regenerative phase of Calvin cycle. A full-length cDNA encoding SBPase (designated as MSBPase, GenBank accession No. DQ995346) was cloned from mulberry (Morus alba var. multicaulis) by rapid amplification of cDNA ends (RACE). The cDNA was 1 527 bp containing a 1 179 bp open reading frame which was deduced for encoding a peptide of 393 amino acids whose molecular mass was inferred to be 42.6 ku with its isoelectric point at 5.85. Sequence comparison analysis showed that the sedoheptulose-1,7-bisphosphatase from mulberry (MSBPase) had high homology to SBPases from other plants. It was prospected that the structure of MSBPase was rich in coils and helixes, and was poor in strands. The coding region of the MSBPase was inserted into an expression vector, pET30a (+), and transformed into Escherichia coli BL2l. The fusion protein was successfully expressed with IPTG induction. The plant expression vector with this fragment under the control of 35S promoter was constructed. The gene cloned in this study may be an asset in the mulberry gene engineering and the results may be helpful to further study the regulation of SBPase.

Key words: Mulberry (Morus alba var. multicaulis), gene cloning, prokaryotic expression, plant expression vector, sedoheptulose-1, 7-bisphosphatase