Expression of c-kit ligand in human keratinocytes.

The c-kit ligand is expressed on tissue-anchored stromal cells. It plays an important role in the development of c-kit-bearing cells, such as haematopoietic cells, germ cells, mast cells and melanocytes. In the present study, we used the reverse transcriptase-mediated polymerase chain reaction (PCR) technique to investigate whether human keratinocytes are able to express c-kit ligand mRNA. Two sets of primers were designed to distinguish two types of c-kit ligand mRNA (full-length type and spliced type). One set was used to amplify an 882-bp DNA fragment from the full-length type, and a 798-bp DNA fragment from the spliced type. Another set was used to amplify a 375-bp DNA fragment from the full-length type only. A cDNA fragment corresponding to the full-length type mRNA was amplified from a cDNA preparation of cultured human keratinocytes as well as from epidermis obtained by the suction blister technique. This result indicates the spontaneous transcription of full-length type mRNA of the c-kit ligand in human keratinocytes.