ANALYSIS OF UVB-MODULATED GENE-EXPRESSION IN HUMAN KERATINOCYTES BY MESSENGER-RNA DIFFERENTIAL DISPLAY POLYMERASE CHAIN-REACTION

Ultraviolet (UV) light is the most important environmental insult to s kin, Even a single exposure to UVB radiation can result in inflammatio n and may also lead to DNA damage and apoptosis in the acute response of the cutaneous tissue. To elucidate the complex alterations of gene expression in human keratinocytes underlying these UV responses we too k advantage of differential display polymerase chain reaction (DD-PCR) technology's ability to detect qualitative and quantitative changes i n gene expression in more than two cell populations simultaneously. We demonstrate that low-dose UVB (100 Jm(-2)) leads to both induction an d downregulation of different genes during the 24 h after irradiation in a time-dependent manner, In addition to the identification of known genes as possible effecters or targets in the UV response of human ke ratinocytes, we here identify a new sequence that is negatively regula ted by UVB irradiation and was termed HUR 7 (HaCaT UV repressed). In g eneral our results showed that DD-PCR is a useful tool in the analysis of quantitative changes of mRNA levels in human keratinocytes after U V irradiation. The identification of new UVB-repressed genes offers th e opportunity to identify unrecognized molecular mechanisms in the UV response of human cells.