Provided is a method for producing a polyisoprenoid, which can increase natural rubber production by enhancing the rubber synthesis activity of rubber particles. The present invention provides methods for producing a polyisoprenoid using a gene coding for a cis-prenyltransferase (CPT) family protein, a gene coding for a Nogo-B receptor (NgBR) family protein and a gene coding for a rubber elongation factor (REF) family protein, specifically a method for producing a polyisoprenoid in vitro using rubber particles bound to proteins coded for by these genes, and a method for producing a polyisoprenoid in vivo using a recombinant organism (plant) having these genes introduced therein.

Disclosed herein are recombinant enzymes derived from various rubber-producing plants and the use of those enzymes in the production of natural rubber outside of plant tissues. Systems and methods for the utilization of these enzymes in the production of natural rubber are also provided.

Provided are a transformant produced by introducing a gene coding for a cis-prenyltransferase and a gene coding for a Nogo-B receptor, which are considered to be involved in polyisoprenoid biosynthesis, into a host to allow the host to express the cis-prenyltransferase and the Nogo-B receptor, and a method for producing a polyisoprenoid using the transformant. The present invention relates to a transformant produced by introducing a gene coding for a cis-prenyltransferase and a gene coding for a Nogo-B receptor into a host to allow the host to express the cis-prenyltransferase and the Nogo-B receptor.

Disclosed herein are recombinant enzymes derived from various rubber-producing plants and the use of those enzymes in the production of natural rubber outside of plant tissues. Systems and methods for the utilization of these enzymes in the production of natural rubber are also provided.

Objects are to provide: a fusion protein capable of binding to lipid droplets while having an enzymatic activity to synthesize a hydrophobic compound; a method for producing a substance including accumulating a hydrophobic compound in lipid droplets using the fusion protein; a vector which can enhance production of a hydrophobic compound when it is introduced into cells using genetic recombination techniques; and a transgenic cell into which the vector or a gene coding for the fusion protein has been introduced. The disclosure relates to a fusion protein having an amino acid sequence (first amino acid sequence) capable of binding to lipid droplets, and an amino acid sequence (second amino acid sequence) having an enzymatic activity to synthesize a hydrophobic compound, the first and second amino acid sequences being fused via a linker sequence (third amino acid sequence) while maintaining the enzymatic activity of the second amino acid sequence.

Provided are a mutant cis-prenyltransferase (CPT) family protein and a method for producing a polyisoprenoid, which enable the production of a high molecular weight polyisoprenoid. Included is a mutant cis-prenyltransferase (CPT) family protein obtained by mutating the amino acid sequence of a C-terminal region of a cis-prenyltransferase (CPT) family protein not found on rubber particles to be identical or similar to the amino acid sequence of a C-terminal region of a cis-prenyltransferase (CPT) family protein found on rubber particles.