Process for constructing a cdna library, and a polypeptide and dna coding for the same

摘要

A process for constructing a cDNA library which has a selectivity for signal peptides, that makes it possible to efficiently identify unknown and useful polypeptide comprising a signal peptide. A novel polypeptide consisting of 89 amino acids (including a signal peptide) produced by a stroma cell line, which is useful as an agent for preventing or treating, for example, anemia, leukopenia or infections and the like, and DNAs coding for said polypeptide, have been identified using the process of the invention.