Paramyxovirus vectors used for transfer of foreign genes

Abstract

A paramyxovirus vector capable of Extransfecting foreign genes and having a replication capacity, is provided. A Sendai virus vector comprising a foreign gene can be constructed by inserting a foreign gene between the viral genes of the Sendai virus genome. These Sendai viruses have a replication capacity and express the foreign gene in transfected cells. The expression level of the foreign gene is higher towards the 3′ end of negative strand RNA, and especially, a high level of expression is obtained when the foreign gene is inserted before the NP gene, and between P gene and M gene. Conversely, the expression decreases towards 5′ end of negative strand RNA, and especially, a relatively low level of expression is obtained when the when the foreign gene is inserted between HN gene and L gene, and between F gene and HN gene. Thus, the vector of the invention enables the regulation of the expression level of a foreign gene. The vector is useful for gene therapy due to its safety, high gene transfer efficiency, and capacity to express a foreign gene at a high level.

What is claimed is:  
     
         1 . A method for regulating the expression level of a foreign gene within a replicable paramyxovirus vector, wherein said method comprises a step of locating the foreign gene downstream of a gene encoding a viral protein in the negative strand genomic RNA contained with said vector.  
     
     
         2 . The method of  claim 1 , wherein said method comprises a step selected from the group consisting of (a) to (f) below, 
 (a) a step of inserting the foreign gene between the 1 st  gene encoding a viral protein and the 2 nd  gene encoding a viral protein from the 3′ end of the negative strand genomic RNA contained within the vector;    (b) a step of inserting the foreign gene between the 2 nd  gene encoding a viral protein and the 3 rd  gene encoding a viral protein from the 3′ end of the negative strand genomic RNA contained within the vector;    (c) a step of inserting the foreign gene between the 3 rd  gene encoding a viral protein and the 4 th  gene encoding a viral protein from the 3′ end of the negative strand genomic RNA contained within the vector;    (d) a step of inserting the foreign gene between the 4 th  gene encoding a viral protein and the 5 th  gene encoding a viral protein from the 3′ end of the negative strand genomic RNA contained within the vector;    (e) a step of inserting the foreign gene between the 5 th  gene encoding a viral protein and the 6 th  gene encoding a viral protein from the 3′ end of the negative strand genomic RNA contained within the vector; and    (f) a step of inserting the foreign gene between the 6 th  gene encoding a viral protein from the 3′ end of the negative strand genomic RNA contained within the vector, and the 5′ end of said negative strand genomic RNA.    
     
     
         3 . The method of  claim 2 , wherein the 1 st  to 6 th  genes encoding viral proteins, counting from the 3′ end to the 5′ end of the negative strand genomic RNA contained within the vector, are in the following order: NP gene, P gene, M gene, F gene, HN gene, and L gene.  
     
     
         4 . The method of  claim 1 , wherein the vector is a Sendai virus vector.