Method for sorting cardiomyocytes

A method for producing cardiomyocytes, comprising the following steps:

• (A) introducing miRNA-responsive mRNA into a cell group, wherein the miRNA-responsive mRNA comprises a sequence having:
• (a) a cap structure;
• (b) a 5′ untranslated region (5′-UTR);
• (c) an open reading frame comprising a nucleic acid corresponding to the coding region of a gene;
• (d) a 3′ untranslated region (3′-UTR);
• and
• (e) a poly (A) tail region,
• wherein the 5′-UTR comprises a nucleic acid specifically recognized by miRNA specifically expressed in cardiomyocytes, and
• wherein the miRNA-responsive mRNA is introduced into the cell group in a form of a synthetic RNA molecule without using a DNA or virus vector;
• (B) inhibiting translation of the coding region of the gene in response to the presence of an miRNA specifically expressed in the cardiomyocytes or performing translation of the coding region of the gene in response to the absence of an miRNA specifically expressed in the cardiomyocytes;
• and
• (C) sorting the cells based on a translation level of a protein from the mRNA of step (A), wherein high-purity cardiomyocytes can be obtained compared with a case in which steps (A), (B), and (C) are not carried out.

A method for producing cardiomyocytes, comprising:

• (A) introducing miRNA-responsive mRNA and mRNA consisting of a sequence comprising a nucleic acid corresponding to the coding region of a drug resistance gene into a cell group, and
• (B) culturing the cell group obtained in step (A) in the presence of a drug corresponding to the drug resistance gene of step (A) wherein the miRNA-responsive mRNA comprises a sequence having:
• (a) a cap structure;
• (b) a 5′ untranslated region (5′-UTR);
• (c) an open reading frame comprising a nucleic acid corresponding to the coding region of a gene;
• (d) a 3′ untranslated region (3′-UTR);
• and
• (e) a poly (A) tail region,
• wherein the 5′-UTR comprises a nucleic acid specifically recognized by miRNA specifically expressed in cardiomyocytes,
• wherein the miRNA-responsive mRNA is introduced into the cell group in a form of a synthetic RNA molecule without using a DNA or virus vector, and
• wherein high-purity cardiomyocytes can be obtained compared with a case in which steps (A) and (B) are not carried out.

A kit for purifying cardiomyocytes, comprising a synthetic miRNA-responsive mRNA, wherein the miRNA-responsive mRNA comprises a sequence having:

• (a) a cap structure;
• (b) a 5′ untranslated region (5′-UTR);
• (c) an open reading frame comprising a nucleic acid corresponding to the coding region of a gene;
• (d) a 3′ untranslated region (3′-UTR);
• and
• (e) a poly (A) tail region,
• wherein the 5′-UTR comprises a nucleic acid specifically recognized by miRNA specifically expressed in cardiomyocytes.