Detection of cryptdin in mouse skin

Defensins are widely distributed and broad-spectrum antimicrobial peptides with activities against bacteria, fungi, and enveloped viruses. Defensins h ave been isolated from granules of neutrophils from humans, rabbits, rats, and guinea pigs, They have also been found in lung macrophages as well as i n Paneth cells of the human, rabbit, and mouse small intestine. The human b eta-defensin-2 was recently isolated from human skin. In this study, we det ected the expression of mRNA for the defensin cryptdin in BALB/c mouse skin by means of reverse transcriptase PCR amplification. Expression was also d etected in dispase-separated epidermis and cultured keratinocytes, but expr ession was not detected in fibroblasts. The expression of cryptdin mRNA was found to begin on embryonic day 17.5. As determined with specific primers, the cDNA sequence cloned from the skin was found to be identical to that p reviously reported for cryptdin-5. cDNA derived from cultured keratinocytes demonstrated the sequences of the cryptdin-6 and cryptdin-1 isoforms, In s itu hybridization analysis showed that the mRNA of cryptdin was expressed i n the suprabasal keratinocytes of the skin in embryonic and neonatal days a nd then shifted to the hair bulbs in the skin of adult mice.