Ultraviolet (UV) B radiation is a dangerous environmental stressor, which can lead
to photoaging, inflammation, immune suppression and tumour formation. A recent report
has shown the transcriptional activation of several skin-specific genes including
matrix metalloproteases (MMPs) in response to UV irradiation. Here, we use a novel
human keratinocyte model, HKerE6SFM, to demonstrate that UVB activates the transcription
of most members of the 11q22.3 MMP gene cluster including MMP13,
MMP12, MMP3, MMP1
and MMP10. Curiously, the expression of the well-characterized
UVB-inducible MMP9, which is located outside of the cluster,
remains unchanged. In accordance with the increased expression of the MMP gene cluster
upon UVB irradiation, RNA polymerase II showed increased occupancy at their promoters
following UVB irradiation. The results also demonstrate increased acetylated histone
H3K9 levels at the promoters of the MMP13, MMP12,
MMP3, MMP1 and MMP10
genes. These findings suggest a coordinated transcriptional activation of genes in
the MMP cluster at 11q22.3 and that acetylation of histone H3 at lysine 9 has an important
role in the UVB-dependent enhancement of transcription of MMP genes in this region.
