Use of AAV replication machinery for improved protein production
The present invention provides a method for enhanced production of a gene product of interest in a cell, using the AAV replication machinery. The present invention further relates to a cell for use in the method of the invention and a non-human transgenic animal or a transgenic plant comprising a cell of the invention.
1. An insect cell that comprises:
(a) a first expression cassette comprising:
(i) a nucleotide sequence encoding a polypeptide of interest;
(ii) a promoter operably linked to said coding nucleotide sequence that is capable of driving expression of the polypeptide of interest in the insect cell; and
(iii) a parvoviral inverted terminal repeat (ITR) nucleotide sequence flanking said expression cassette on both sides;
and
(b) a second expression cassette that comprises:
(i) a nucleotide sequence encoding at least one parvoviral Rep protein; and
(ii) a promoter operably linked to said nucleotide sequence encoding said Rep protein that is capable of driving expression of the Rep protein in the insect cell;
which insect cell does not comprise a parvoviral Cap protein or a nucleotide sequence encoding a parvoviral Cap protein, and
wherein the expression of the polypeptide of interest is increased, as compared to an insect cell which comprises said nucleotide encoding said polypeptide of interest and said promoter operably linked thereto and said flanking parvoviral ITR sequence but differs in that it does not comprise said nucleotide sequence encoding said at least one parvoviral Rep protein operably linked to said promoter capable of driving expression of the Rep protein in said cell.
2. A method for producing a polypeptide of interest in an insect cell, comprising culturing the insect cell according to claim 1 under conditions that are conducive for expression of the first and the second expression cassettes, thereby attaining said increased expression and production of said polypeptide of interest.
3. The method according to claim 2 further comprising recovering said polypeptide of interest from the culture.
4. The method according to claim 2 , wherein the second expression cassette comprises an open reading frame comprising nucleotide sequences encoding Rep78 and/or Rep68 proteins.
5. The method according to claim 2 , wherein the first and the second expression cassettes are present in a single construct that is flanked by a parvoviral ITR sequence on each side.
6. The method according to claim 2 , wherein the parvoviral ITR sequence and parvoviral Rep protein are from an adeno-associated virus.
7. The method according to claim 2 , wherein at least one of the expression cassettes is comprised in a baculoviral vector.