Hatanaka, Y. | bioRxiv Science

bioRxiv2021

Violet light modulates the central nervous system to regulate memory and mood

Light stimuli from the external environment serves as a signal. Photoreceptors receive photons at the outer nuclear layer of the retina. Non-visual photoreceptors, such as opsin5 (also known as OPN5 or neuropsin), are expressed in the retinal ganglion cells (RGCs) and hypothalamus to regulate the circadian cycle and body temperature. Here, we show that violet light (VL) stimuli received by OPN5-positive RGCs are transmitted to the habenula brain region. VL improves memory in aged mice and simultaneously increases neural architecture-related genes such as oligodendrocyte-related genes in the hippocampus. In addition, VL improves depressive-like behaviors in the social defeat stress model in an OPN5 dependent manner. Following VL exposure, cFos activation is observed at the nucleus accumbens (NAc) and the paraventricular thalamic nucleus (PVT). Taken together, the results indicate that violet light modulates brain function such as memory and mood by transmitting the signal from RGCs to the habenula region in the brain.

neuroscience↗

bioRxiv2020

Global regulatory transitions at core promoters demarcate the mammalian germline cycle

Core promoters integrate regulatory inputs of genes1-3. Global dynamics of promoter usage can reveal systemic changes in how genomic sequence is interpreted by the cell4 Here we report the first analysis of promoter dynamics and code switching in the mammalian germ line, characterising the full cycle of transitions from embryonic stem cells through germline, oogenesis, and zygotic genome activation. Using Super Low Input Carrier-CAGE5,6 (SLIC-CAGE) we show that mouse germline development starts with the somatic promoter code, followed by a prominent switch to the maternal code during follicular oogenesis. The sequence features underlying the shift from somatic to maternal code are conserved across vertebrates, despite large differences in promoter nucleotide compositions. In addition, we show that, prior to this major shift, the promoters of gonadal germ cells diverge from the canonical somatic transcription initiation. This divergence is distinct from the promoter code used later by developing oocytes and reveals genome-wide promoter remodelling associated with alternative nucleosome positioning during early female and male germline development. Collectively, our findings establish promoter-level regulatory transitions as a central, conserved feature of the vertebrate life cycle.

developmental biology↗