PCT No. PCT / JP97 / 03992 Sec. 371 Date Jul. 16, 1999 Sec. 102(e) Date Jul. 16, 1999 PCT Filed Oct. 31, 1997 PCT Pub. No. WO98 / 20122 PCT Pub. Date May 14, 1998Disclose is a method for making full-length cDNA libraries, which is for making libraries of cDNAs having lengths corresponding to full lengths of mRNAs and comprises the following steps of; forming
RNA-
DNA hybrids by reverse transcription starting from primers using mRNAs as templates, chemically binding a tag molecule to a
diol structure present in the 5' Cap (7MeGpppN) site of a mRNA which is forming a
RNA-
DNA hybrid, and separating
RNA-
DNA hybrids carrying
a DNA corresponding to a full-length mRNA from the RNA-DNA hybrids formed above by using a function of the tag molecule. The
present method is a method for preparing full-length cDNA libraries utilizing a method for labeling the 5' Cap site more efficiently than
protein enzyme reactions, which is avoidable a decrease of a full-length cDNA synthesis efficiency caused by cleavage of mRNA, and can synthesize a full-length cDNA more efficiently.