Chimeric Retinoid X Receptors and Their Use in a Novel Ecdysone Receptor-Based Inducible Gene Expression System

Abstract

This invention relates to the field of biotechnology or genetic engineering. Specifically, this invention relates to the field of gene expression. More specifically, this invention relates to a novel ecdysone receptor/chimeric retinoid X receptor-based inducible gene expression system and methods of modulating gene expression in a host cell for applications such as gene therapy, large-scale production of proteins and antibodies, cell-based high throughput screening assays, functional genomics and regulation of traits in transgenic organisms.

1 .- 35 . (canceled) 
     
     
         36 . An isolated polynucleotide selected from the group consisting of:
 (a) a polynucleotide encoding a truncated chimeric retinoid X receptor ligand binding domain comprising a truncation mutation, wherein the truncation mutation reduces ligand binding activity of the truncated chimeric retinoid X receptor ligand binding domain;   (b) a polynucleotide encoding a truncated chimeric retinoid X receptor ligand binding domain comprising a truncation mutation, wherein the truncation mutation reduces steroid binding activity of the truncated chimeric retinoid X receptor ligand binding domain;   (c) a polynucleotide encoding a truncated chimeric retinoid X receptor ligand binding domain comprising a truncation mutation, wherein the truncation mutation reduces non-steroid binding activity of the truncated chimeric retinoid X receptor ligand binding domain;   (d) a polynucleotide encoding a truncated chimeric retinoid X receptor ligand binding domain comprising a truncation mutation, wherein the truncation mutation enhances ligand binding activity of the truncated chimeric retinoid X receptor ligand binding domain;   (e) a polynucleotide encoding a truncated chimeric retinoid X receptor ligand binding domain comprising a truncation mutation, wherein the truncation mutation enhances steroid binding activity of the truncated chimeric retinoid X receptor ligand binding domain;   (f) a polynucleotide encoding a truncated chimeric retinoid X receptor ligand binding domain comprising truncation mutation, wherein the truncation mutation enhances non-steroid binding activity of the truncated chimeric retinoid X receptor ligand binding domain;   (g) a polynucleotide encoding a truncated chimeric retinoid X receptor ligand binding domain comprising a truncation mutation, wherein the truncation mutation increases ligand sensitivity of the truncated chimeric retinoid X receptor ligand binding domain; and   (h) a polynucleotide encoding a truncated chimeric retinoid X receptor ligand binding domain comprising a truncation mutation, wherein the truncation mutation increases ligand sensitivity of a heterodimer wherein the heterodimer comprises the truncated chimeric retinoid X receptor ligand binding domain and a dimerization partner.   
     
     
         37 .- 44 . (canceled) 
     
     
         45 . An isolated polynucleotide encoding a chimeric retinoid X receptor ligand binding domain, wherein the polynucleotide comprises a nucleic acid sequence selected from the group consisting of
 (a) nucleotides 1-348 of SEQ ID NO: 13 and nucleotides 268-630 of SEQ ID NO: 21,   (b) nucleotides 1-408 of SEQ ID NO: 13 and nucleotides 337-630 of SEQ ID NO: 21,   (c) nucleotides 1-465 of SEQ ID NO: 13 and nucleotides 403-630 of SEQ ID NO: 21,   (d) nucleotides 1-555 of SEQ ID NO: 13 and nucleotides 490-630 of SEQ ID NO 21,   (e) nucleotides 1-624 of SEQ ID NO 13 and nucleotides 547-630 of SEQ ID NO 21,   (f) nucleotides 1-645 of SEQ ID NO: 13 and nucleotides 601-630 of SEQ ID NO: 21, and   (g) nucleotides 1-717 of SEQ ID NO: 13 and nucleotides 613-630 of SEQ ID NO: 21.   
     
     
         46 . (canceled) 
     
     
         47 . An isolated polynucleotide encoding a chimeric retinoid X receptor ligand binding domain comprising an amino acid sequence selected from the group consisting of
 (a) amino acids 1-116 of SEQ ID NO: 19 and amino acids 90-210 of SEQ ID NO: 27,   (b) amino acids 1-136 of SEQ ID NO: 19 and amino acids 113-210 of SEQ ID NO: 27,   (c) amino acids 1-155 of SEQ ID NO: 19 and amino acids 135-210 of SEQ ID NO: 27,   (d) amino acids 1-185 of SEQ ID NO: 19 and amino acids 164-210 of SEQ ID NO: 27,   (e) amino acids 1-208 of SEQ ID NO: 19 and amino acids 183-210 of SEQ ID NO: 27,   (f) amino acids 1-215 of SEQ ID NO: 19 and amino acids 201-210 of SEQ ID NO: 27, and   (g) amino acids 1-239 of SEQ ID NO 19 and amino acids 205-210 of SEQ ID NO 27.   
     
     
         48 - 65 . (canceled) 
     
     
         66 . The isolated polynucleotide of  claim 47 , wherein the polynucleotide encodes a chimeric retinoid X receptor ligand binding domain comprising amino acids 1-116 of SEQ ID NO 19 and amino acids 90-210 of SEQ ID NO 27. 
     
     
         67 . The isolated polynucleotide of  claim 47 , wherein the polynucleotide encodes a chimeric retinoid X receptor ligand binding domain comprising amino acids 1-136 of SEQ ID NO: 19 and amino acids 113-210 of SEQ ID NO: 27. 
     
     
         68 . The isolated polynucleotide of  claim 47 , wherein the polynucleotide encodes a chimeric retinoid X receptor ligand binding domain comprising amino acids 1-155 of SEQ ID NO 19 and amino acids 135-210 of SEQ ID NO: 27. 
     
     
         69 . The isolated polynucleotide of  claim 47 , wherein the polynucleotide encodes a chimeric retinoid X receptor ligand binding domain comprising amino acids 1-185 of SEQ ID NO: 19 and amino acids 164-210 of SEQ ID NO: 27. 
     
     
         70 . The isolated polynucleotide of  claim 47 , wherein the polynucleotide encodes a chimeric retinoid X receptor ligand binding domain comprising amino acids 1-208 of SEQ ID NO: 19 and amino acids 183-210 of SEQ ID NO: 27. 
     
     
         71 . The isolated polynucleotide of  claim 47 , wherein the polynucleotide encodes a chimeric retinoid X receptor ligand binding domain comprising amino acids 1-215 of SEQ ID NO: 19 and amino acids 201-210 of SEQ ID NO: 27. 
     
     
         72 . The isolated polynucleotide of  claim 47 , wherein the polynucleotide encodes a chimeric retinoid X receptor ligand binding domain comprising amino acids 1-208 of SEQ ID NO: 19 and amino acids 183-210 of SEQ ID NO: 27. 
     
     
         73 . The isolated polynucleotide of  claim 47 , wherein the polynucleotide encodes a chimeric retinoid X receptor ligand binding domain comprising amino acids 1-215 of SEQ ID NO: 19 and amino acids 201-210 of SEQ ID NO: 27. 
     
     
         74 . The isolated polynucleotide of  claim 47 , wherein the polynucleotide encodes a chimeric retinoid X receptor ligand binding domain comprising amino acids 1-239 of SEQ ID NO: 19 and amino acids 205-210 of SEQ ID NO: 27.