Novel modified nucleic acid sequences and methods for increasing mRNA levels and protein expression in cell systems
4 Assignments
0 Petitions
Accused Products
Abstract
The invention provides modified recombinant nucleic acid sequences (preferably DNA) and methods for increasing the mRNA levels and protein expression of proteins which are known to be, or are likely to be, difficult to express in cell culture systems, mammalian cell culture systems, or in transgenic animals. The preferred “difficult” protein candidates for expression using the recombinant techniques of the invention are those proteins derived from heterologous cells preferably those of lower organisms such as parasites, bacteria, and virus, having DNA coding sequences comprising high overall AT content or AT rich regions and/or mRNA instability motifs and/or rare codons relative to the recombinant expression system to be used.
-
Citations
73 Claims
-
1-26. -26. (Cancelled)
-
27. A method for producing a parasite protein or fragment thereof in milk of a non-human transgenic mammal, comprising:
providing said non-human transgenic mammal whose genome comprises a modified nucleic acid sequence encoding said parasite protein or fragment thereof operably linked to a promoter which directs expression in a mammary gland, wherein said modified nucleic acid sequence has been modified by replacing one or more AT-containing codons of the nucleic acid sequence of said parasite protein or fragment thereof as it naturally occurs in a parasite with a codon or codons preferred by a mammalian cell for the purposes of expression and encoding the same parasite protein or fragment thereof as derived from said parasite; and
allowing said non-human transgenic mammal to express said parasite protein or fragment thereof in its milk, to thereby produce said parasite protein or fragment thereof.- View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
-
39. A method for producing a parasite protein or fragment thereof in the milk of a non-human transgenic mammal, comprising:
-
providing said non-human transgenic mammal whose genome comprises a modified nucleic acid sequence encoding said parasite protein or fragment thereof operably linked to a promoter which directs expression in a mammary gland, wherein said nucleic acid sequence of said parasite protein or fragment thereof has been modified by replacing at least a portion of an AUUUA mRNA instability motif in a coding sequence of said parasite protein or fragment thereof as it naturally occurs in a parasite with a codon or codons preferred by a mammalian cell for the purposes of expression so as to remove said AUUUA mRNA instability motif or prevent said AUUUA mRNA instability motif from destabilizing mRNAs encoding said parasite protein or fragment thereof while encoding an amino acid which is the same as the replaced portion of said AUUUA mRNA instability motif;
allowing said non-human transgenic mammal to express said parasite protein or fragment thereof in its milk, to thereby produce said parasite protein or fragment thereof, and wherein the naturally occurring nucleic acid sequence encoding said parasite protein or fragment thereof contains at least one AUUUA instability motif; and
, - View Dependent Claims (40, 41, 42, 43, 44, 45)
-
-
46. A method for producing a parasite protein or fragment thereof in the milk of a non-human transgenic mammal, comprising:
providing a non-human transgenic mammal whose genome comprises a modified nucleic acid sequence encoding said parasite protein or fragment thereof operably linked to a promoter which directs expression in a mammary gland, wherein said modified nucleic acid sequence has been modified by;
a) replacing at least a portion of an AUUUA mRNA instability motif in the coding sequence of said parasite protein or fragment thereof as it naturally occurs in a parasite with a codon or codons preferred by a mammalian cell for the purposes of expression so as to remove said AUUUA mRNA instability motif or prevent said AUUUA mRNA instability motif from destabilizing mRNAs encoding said parasite protein or fragment thereof while encoding the same amino acid as the replaced portion of said AUUUA mRNA instability motif;
b) replacing one or more AT-containing codons of said modified nucleic acid sequence as it naturally occurs in said parasite with a codon or codons preferred by a mammalian cell for the purposes of expression and encoding the same amino acid as the replaced codon;
c) allowing said non-human transgenic mammal to express said parasite protein or fragment thereof in its milk, to thereby produce said parasite protein or fragment thereof and wherein the naturally occurring nucleic acid sequence encoding said parasite protein or fragment thereof contains at least one AUUUA instability motif; and
,- View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59)
- 60. A transgenic non-human mammal whose germline comprises a modified nucleic acid sequence encoding a parasite protein or fragment thereof operably linked to a promoter which directs expression in a mammary gland, wherein said modified nucleic acid sequence has been modified by replacing at least a portion of an AUUUA mRNA instability motif in a coding sequence as it naturally occurs in a parasite with a codon or codons preferred by a mammalian cell for the purposes of expression so as to remove said AUUUA mRNA instability motif or prevent said AUUUA mRNA instability motif from destabilizing mRNAs encoding said parasite protein or fragment thereof while encoding the same amino acid as the replaced portion of said AUUUA mRNA instability motif and by replacing one or more AT-containing codons of the nucleic acid sequence of said parasite protein or fragment thereof as it naturally occurs in the parasite with a codon or codons preferred by a mammalian cell for the purposes of expression and encoding the same amino acid as the replaced codon, wherein said non-human transgenic mammal expresses said parasite protein or fragment thereof in its milk and wherein the naturally occurring nucleic acid sequence encoding said parasite protein or fragment thereof contains at least one AUUUA instability motif;
Specification