Many animals change their body pigmentation according to illumination of their environment. In aquatic vertebrates, this reaction is mediated through aggregation or dispersion of melanin-filled vesicles (melanosomes) in dermal pigment cells (melanophores). The adaptive value of this behavior is usually seen in camouflage by allowing the animal to visually blend into the background. When exposed...

PURPOSE To investigate the protective effect of a blue-light filtering intraocular lens (yellow IOL) (YA60BB, Hoya) and an ultraviolet (UV)-absorbing IOL (VA60BB, Hoya) on light-induced phototoxicity to retinal pigment epithelial (RPE) cells laden with the lipofuscin fluorophore A2E and on the production of vascular endothelial growth factor (VEGF) after light exposure. SETTING University of ...

Excessive sun tanning can result in addictive behavior. In this issue of Cell, Fell et al. utilize a combination of behavioral pharmacology and transgenic mice to demonstrate that chronic UV light exposure recruits p53 signaling in keratinocytes, subsequently increasing β-endorphin signaling at opioid receptors, and produces an endogenous opioid-dependent state.

Exposure of human skin to low doses of solar UV radiation (UVR) causes increased pigmentation, while chronic exposure is a powerful risk factor for skin cancers. The mechanisms mediating UVR detection in skin, however, remain poorly understood. Our recent studies revealed that UVR activates a retinal-dependent G protein-coupled signaling pathway in melanocytes. This phototransduction pathway le...

We developed a transcript profiling methodology to elucidate expression patterns of the cyanobacterium Synechocystis sp. strain PCC 6803 and used the technology to investigate changes in gene expression caused by irradiation with either intermediate-wavelength UV light (UV-B) or high-intensity white light. Several families of transcripts were altered by UV-B treatment, including mRNAs specifyin...

A means to control lysozyme conformation with light illumination has been developed using the interaction of the protein with a photoresponsive surfactant. Upon exposure to the appropriate wavelength of light, the azobenzene surfactant undergoes a reversible photoisomerization, with the visible-light (trans) form being more hydrophobic than the UV-light (cis) form. As a result, surfactant bindi...

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People exposed to sunlight can develop erythema, DNA damage, and photoimmunosupression. Extended exposure of normal epidermis to sunlight will induce dysmorphic keratinocytes with pyknotic nuclei scattered throughout the spinous layer. These 'sunburn cells' are apoptotic keratinocytes and are usually cleared within 48 hours after sunburn. Patients with lupus erythematosus, however, whether it b...

After DNA damage, cells modulate pre-messenger RNA (pre-mRNA) splicing to induce an anti- or proapoptotic response. In this issue, Muñoz et al. (2009) uncover a cotranscriptional mechanism for activating alternative pre-mRNA splicing after ultraviolet irradiation that depends unexpectedly on hyperphosphorylation of the RNA polymerase II C-terminal domain and decreased rates of transcription elo...