title: Sparus aurata, Skin, UVB (6 kj/m2/d) Replicate 2
design: S. aurata juveniles were exposed for 43 days to two experimental groups: 1) UVB (daily dose, 6 kJ m-2; representing levels between 5 and 7 m depth); 2) Unirradiated treatment, used as a control. Total RNA was isolated from the skin (30-40 mg) of control and UVB-exposed fish. RNA extraction and purification were optimized by combining both TRIzol (Sigma, USA) and RNeasy PowerLyzer Tissue & Cells Kit (Qiagen, Germany). 10 _g of total RNA was treated with a Turbo DNA-free kit (Invitrogen, USA) and purified with the RNeasy PowerClean  Pro Cleanup Kit (Qiagen, Germany), preventing contamination with genomic DNA. RNA concentration and purity were determined using the Qubit RNA BR Assay Kit (Thermo Scientific, USA) and Nanodrop 2000c (Thermo Scientific, USA), respectively. OD 260/280 and OD 260/230 ranged between 2.08-2.12 and 2.15-2.22, respectively. The integrity and concentration were verified with an Agilent 2100 Bioanalyzer (Agilent Technologies, USA). For all the samples, RIN (RNA integrity number) values were equal to or above 8. Four biological replicates from each treatment (Control, UVB) were selected for library preparation and RNA sequencing was based on the highest RNA quality and integrity scores. A total of eight libraries were prepared from 1 _g of total RNA using the Illumina TruSeq Stranded mRNA LT Sample Prep Kit (Illumina, USA) according to the manufacturers instructions. The quality of each library was confirmed using the Agilent 2100 Bioanalyzer (Agilent Technologies, USA). All the eight RNA-seq libraries were pooled (average size, 337-407 bp inserts). After generating the clusters, libraries were sequenced on the Illumina HiSeq 4000 platform (Illumina, USA), to create paired-end reads (2 x 150 bp). Image analysis and base calling were done using the Illumina pipeline. The RNA sequencing was performed at the KAUST Bioscience Core Labs.