Biology subjects

Odaka, Y.

Publications and source records attributed to Odaka, Y..

3 recordsLinked to original sources

bioRxiv2021

A Drosophila Su(H) Model of Adams-Oliver Syndrome Reveals Notch Cofactor Titration as a Mechanism Underlying Developmental Defects

Notch signaling is a conserved pathway that converts extracellular receptor-ligand interactions into changes in gene expression via a single transcription factor (CBF1/RBPJ in mammals; Su(H) in Drosophila). In humans, RBPJ variants have been linked to Adams-Oliver syndrome (AOS), a rare autosomal dominant disorder characterized by scalp, cranium, and limb defects. Here, we found that a previously described Drosophila Su(H) allele encodes a missense mutation that alters an analogous residue found in an AOS-associated RBPJ variant. Importantly, genetic studies support a model that Drosophila with a single copy of the AOS-like Su(H) allele behave in an opposing manner as flies with a Su(H) null allele due to a dominant activity of sequestering either the Notch co-activator or the antagonistic Hairless co-repressor. Consistent with this model, AOS-like Su(H) and Rbpj variants decrease DNA binding activity compared to wild type proteins, but these variants do not significantly alter protein binding to the Notch co-activator or the fly and mammalian co-repressors, respectively. Taken together, these data suggest a cofactor sequestration mechanism underlies AOS phenotypes associated with RBPJ variants, whereby a single RBPJ allele encodes a protein with compromised DNA binding activity that retains cofactor binding, resulting in Notch target gene dysregulation.

genetics↗

bioRxiv2019

Adaptive thermogenesis in mice requires adipocyte light-sensing via Opsin 3

Almost all life forms can decode light information for adaptive advantage. Examples include the visual system, where photoreceptor signals are interpreted as images, and the circadian system, where light entrains a physiological clock. Here we describe a local, non-visual light response in mice that employs encephalopsin (OPN3, a 480 nm, blue light responsive opsin) to regulate the function of adipocytes. Germ line null and adipocyte-specific conditional null mice show a deficit in thermogenesis that is phenocopied in mice under blue-light deficient conditions. We show that blue light stimulation of adipocytes activates hormone sensitive lipase, the rate limiting enzyme in the lipolysis pathway, and that this is OPN3-dependent. Opn3 adipocyte conditional null mice also use reduced levels of fat mass when fasted and cold exposed further suggesting a lipolysis deficit. These data suggest the hypothesis that in mice, a local, OPN3-dependent light response in adipocytes is a mechanism for regulation of energy homeostasis.

physiology↗

bioRxiv2018

An adipocyte light-Opsin 3 pathway regulates the circadian clock and energy balance.

Almost all life forms can detect and decode light information for adaptive advantage. Examples include the visual system, where photoreceptor signals are processed into virtual images, and the circadian system, where light entrains a physiological clock. Here we describe a pathway in mice that employs encephalopsin (OPN3, a 480 nm light responsive opsin) to mediate light responses in murine adipocytes. The adipocyte light-OPN3 pathway regulates neonatal growth in mice and is required for at least three important functions including (1) photoentrainment of a local circadian clock, (2) extracellular matrix deposition, and (3) regulation of mitochondrial content and the proportion of \"brite\" adipocytes. Furthermore, we show that the light-OPN3 pathway is required for normal levels of uncoupling protein 1 (UCP1) in white and brown adipose tissue. Consequently, neonatal Opn3 germ-line and adipocyte-conditional null mice show a reduced ability to maintain their body temperature under cold stress. This was also observed in wild-type mice deprived of blue light. We hypothesize that the adipocyte light-OPN3 pathway provides a dynamically responsive, circadian clock-integrated mechanism for regulating adipocyte function and in turn directing metabolism to thermogenesis rather than anabolism. These data indicate an important role for peripheral light sensing in mammals and may have broad implications for human health given the unnatural lighting conditions in which we live.

physiology↗