| 摘要 |
PROBLEM TO BE SOLVED: To obtain a new DNA fragment having each specific base sequence and molecular weight, coding a protein having activity to proliferate, differentiate and induce thymus macrophage-based cells and cerebral microglia cells, and useful for e.g. cloning the corresponding DNA. SOLUTION: This new DNA fragment, which has a molecular weight (determined by SDS-polyacrylamide gel electrophoresis) of about 60000 dalton and codes a polypeptide derived from a protein having activity to proliferate differentiate and induce thymus macrophage-based cells and cerebral microglia cells singly, or a polypeptide having an amino acid sequence homologous with that of the above polypeptide, is useful for cloning the cDNA and genome DNA each corresponding to the protein bearing the above-mentioned activity. This DNA fragment is obtained by the following process: mRNA is isolated by conventional means from peritubular contractile cells capable of producing the protein, the corresponding cDNA is synthesized by using the mRNA, and then cloned by PCR process using a primer obtained with the cDNA as template. |
