Aim: To identify the genes and non-coding RNAs (ncRNAs) involved in the neuroprotective actions of a dietary anti-oxidant (saffron) and of photobiomodulation.
Gene and noncoding RNA regulation underlying photoreceptor protection: microarray study of dietary antioxidant saffron and photobiomodulation in rat retina.
Specimen partView Samples
The retinas of simian primates include a specialized, cone-rich, macula which regards the central visual field and mediates high acuity and colour vision. A prominent feature of the macula is the fovea centralis - a 1 mm-wide, avascular depression in the inner retinal surface that corresponds with a local absence of rods and a peak spatial density of cones in the outer photoreceptor layer. The arrangement of macular photoreceptors, and their specialized midget circuits, are the neural substrate for high resolution vision in primates. Macular-specific photoreceptor loss and abnormal blood vessel growth within the macula are the major causes of untreatable vision loss worldwide. However, the genes that regulate specialization of the macula, and the causes of its vulnerability to degeneration, remain obscure. Microarrays were used to compare gene expression between macula and non-macular regions during a critical phase of human retinal vascular development.
Differential expression of anti-angiogenic factors and guidance genes in the developing macula.
Specimen partView Samples
PURPOSE: Hyperoxia is toxic to photoreceptors, and this toxicity may be important in the progress of retinal dystrophies. This microarray study examines gene expression induced in the C57BL/6J mouse retina by hyperoxia over the 14-day period during which photoreceptors first resist, then succumb to, hyperoxia. METHODS: Young adult C57BL/6J mice were exposed to hyperoxia (75% oxygen) for up to 14 days. On day 0 (control), day 3, day 7, and day 14, retinal RNA was extracted and processed on Affymetrix GeneChip Mouse Genome 430 2.0 arrays. Microarray data were analyzed using GCOS Version 1.4 and GeneSpring Version 7.3.1. RESULTS: The overall numbers of hyperoxia-regulated genes increased monotonically with exposure. Within that increase, however, a distinctive temporal pattern was apparent. At 3 days exposure, there was prominent upregulation of genes associated with neuroprotection. By day 14, these early-responsive genes were downregulated, and genes related to cell death were strongly expressed. At day 7, the regulation of these genes was mixed, indicating a possible transition period from stability at day 3 to degeneration at day 14. CONCLUSIONS: Microarray analysis of the response of the retina to prolonged hyperoxia demonstrated a temporal pattern involving early neuroprotection and later cell death, and provided insight into the mechanisms involved in the two phases of response. As hyperoxia is a consistent feature of the late stages of photoreceptor degenerations, understanding the mechanisms of oxygen toxicity may be important therapeutically.
Gene regulation induced in the C57BL/6J mouse retina by hyperoxia: a temporal microarray study.
Specimen partView Samples
Chromatin performs numerous functions during cellular differentiation, and therefore it must be capable of adopting a multitude of different structures. How these various structures are established is poorly understood, but we propose that specific histone H2A variants will have a key role in remodelling chromatin during differentiation. Structurally, we show here that the gain of just a single acidic amino acid residue has generated a new mouse H2A.Bbd-like histone variant, H2A.Lap1, and that when incorporated into nucleosomal arrays imparts on them unique biophysical properties that are distinct from arrays containing either H2A or human H2A.Bbd. Functionally, we identify H2A.Lap1 as a novel chromatin component of active genes that are expressed during spermatogenesis, and in combination with H2A.Z create a unique chromatin landscape at the start site of transcription. During round spermatid differentiation, H2A.Lap1 dramatically loads onto the inactive X chromosome enabling a subset of its genes to be transcriptionally activated.
A unique H2A histone variant occupies the transcriptional start site of active genes.
Sex, Age, Specimen partView Samples
IgG cytoplasmic tail interferes with the induction of antigen-response genes
Enhancement and suppression of signaling by the conserved tail of IgG memory-type B cell antigen receptors.
No sample metadata fieldsView Samples
In this study we used genetic approaches and transcriptome profiling to unravel the complex interaction of different developmental pathways required for chloroplast development in plants. The recently described snowy cotyledon 3 (sco3) mutant as well as the Phytochrome B (phyb) mutant revealed, in the double mutant, a complex suppressive or additive genetically linked regulation of chloroplast development, flowering time and transcription regulation.
No associated publication
Age, Specimen partView Samples