This cDNA library (plasmid DNA) is constructed from human TIG-1 cell (fetal lung fibroblast primary culture)-derived poly(A)+ RNA by the Linker-Primer method by Professor Hiroshi Nojima of Research Institute for Microbial Diseases Osaka University. This library is unidirectionally cloned by using the oligo (dT)18 linker primer which contains the restriction enzyme site of Not I and BamHI (Bgl II)-Sma I adaptor. The pBA3 vector used in this library has pUC ori which enables replication in E. coli and Ampr as a selection marker. Application: PCR screening of known or unknown gene: Prepare the primers for the known or unknown gene (cDNA) and amplify the gene by PCR from this library followed by cloning to an appropriate vector. It is useful for large-scale protein productions and preparation of probes etc. Standard amplifying conditions: 35 cycles of PCR reactions using 10-100 ng of cDNA as a template. (Change the quantity of template and the number of cycles depending on the expression rate of mRNA of the objective gene.)