Composition for nucleic acid transfection

Abstract

The invention provides a nucleic-acid-transfecting composition which exhibits low cytotoxicity, which facilitates an effective nucleic acid transfection into a cell, and which improves expression of the nucleic acid in the cell. The composition for transfecting a nucleic acid into a cell, contains a di(C 12-16 alkyl)dimethylammonium halide and a phospholipid.

1 . A composition for transfecting a nucleic acid into a cell, comprising a di(C 12-16  alkyl)dimethylammonium halide and a phospholipid. 
     
     
         2 . The composition as described in  claim 1 , which further comprises cholesterol and/or cholestanol in an amount of 0 to 50 mol % on the basis of the total lipid content of the composition. 
     
     
         3 . The composition as described in  claim 1 , wherein the amount of di(C 12-16  alkyl)dimethylammonium halide is 30 to 50 mol % on the basis of the total lipid content of the composition. 
     
     
         4 . The composition as described in  claim 1 , wherein the ratio by mole of the di(C 12-16  alkyl)dimethylammonium halide to the phospholipid is 2:3 to 3:2. 
     
     
         5 . The composition as described in  claim 1 , wherein the di(C 12-16  alkyl)dimethylammonium halide is ditetradecyldimethylammonium halide. 
     
     
         6 . The composition as described in  claim 1 , wherein the di(C 12-16  alkyl)dimethylammonium halide is ditetradecyldimethylammonium bromide. 
     
     
         7 . The composition as described in  claim 1 , wherein the phospholipid is one or more species selected from phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphatidylglycerol, cardiolipin, sphingomyelin, plasmalogen, and phosphatidic acid. 
     
     
         8 . The composition as described in  claim 1 , wherein the phospholipid is phosphatidylethanolamine. 
     
     
         9 . The composition as described in  claim 1 , wherein the phospholipid is dioleoylphosphatidylethanolamine. 
     
     
         10 . The composition as described in  claim 1 , which further comprises an enhancer. 
     
     
         11 . The composition as described in  claim 10 , wherein the enhancer is one or more species selected from among poly L-lysine, protamine or a salt thereof, pronectin, spermine, a nuclear localization signal (NLS), and sodium butyrate. 
     
     
         12 . The composition as described in  claim 10 , wherein the enhancer contains protamine or a salt thereof. 
     
     
         13 . A composition for transfecting a nucleic acid into a cell, comprising ditetradecyldimethylammonium bromide, dioleoylphosphatidylethanolamine, and cholesterol. 
     
     
         14 . A composition for transfecting a nucleic acid into a cell, comprising ditetradecyldimethylammonium bromide, dioleoylphosphatidylethanolamine, cholesterol, and protamine. 
     
     
         15 . The composition as described in  claim 1 , which further comprises a nucleic acid. 
     
     
         16 . The composition as described in  claim 15 , wherein the nucleic acid is a gene or a short oligonucleotide. 
     
     
         17 . The composition as described in  claim 1 , which is in the form of a lipid membrane structure. 
     
     
         18 . The composition as described in  claim 1 , which is in the form of a liposome. 
     
     
         19 . The composition as described in  claim 1 , which is a lyophilized product. 
     
     
         20 . A method for transfecting a nucleic acid into a cell, comprising applying a composition as recited in  claim 15  to a cell in vitro or in vivo. 
     
     
         21 . A nucleic-acid-transfecting agent comprising a composition as recited in  claim 1 . 
     
     
         22 . A screening method for selecting a substance which increases or inhibits expression of a target nucleic acid, comprising the following steps (1) to (3):
 (1) a step of bringing a test substance into contact with a cell into which a target nucleic acid has been transfected;   (2) a step of determining the level of expression of the target nucleic acid in the cell which has been brought into contact with the test substance; and   (3) a step of selecting a test substance showing an expression level as determined in (2) that is higher or lower than the level of expression of the target nucleic acid in a control cell, wherein transfection of the target nucleic acid into the cell and/or exposure of the cell to the test substance is carried out by use of a composition as recited in  claim 1 .