Vector-Capping: A Simple Method for Preparing a High-Quality Full-Length cDNA Library

Full-length cDNAs play an essential role in identifying genes and determining their promoter regions. Here we describe a simple method for constructing a full-length cDNA library, which has the following advantages: (i) it consists of only three steps including direct ligation between a vector and a cDNA strand using T4 RNA ligase, (ii) it contains neither a PCR process generating mutations nor restriction enzyme treatment causing truncation of cDNA, (iii) the intactness of cDNA is assured due to the presence of an additional dGMP at its 5 � end, (iv) approximately 95% of cDNA clones are full-length when cultured cells or fresh tissues are used, (v) several micrograms of total RNA without mRNA purification is sufficient for preparation of a library containing >10 5 independent clones, and (vi) a long-sized full-length cDNA up to 9.5 kbp can be cloned. This method will accelerate comprehensive gene analysis in a variety of eukaryotes.