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Dr. Sakina GooljarResearch Fellow.
My background is in photoreception, opsins and in rodent models of retinal degeneration. My PhD was primarily concerned with light perception in the absence of rods and cones and following severe retinal cell loss in aged retinally degenerate mice. This work involved using behavioural assays (pupillary light reflex, and light entrainment of circadian locomotor behaviour) to assess light perception as well as functional neuroanatomy to elucidate light responsive neurons within the retina and the brain of retinal degenerates. To complement this work I have used molecular techniques to assess changes in gene expression and also cloning to isolate the full coding sequence of opsins. More recently my work has involved the discovery and characterization of a new population of cone photopigment expressing cells (found in rodents and humans) in the inner retina.
In the London Project my role as Research Fellow will primarily be concerned with differentiating and isolating photoreceptors from the human ES cells. I plan to employ molecular and histological techniques to assess their expression of key photoreceptor specific genes followed by electrophysiological recordings (in collaboration with Prof. Peter Mobbs) to assess their response to light. Finally we plan to transplant these differentiated cells into the retina of rodent models of retinal degeneration and to determine their efficacy in augmenting light sensitivity.
Co-discovery (with Dr. Anthony Vugler) and characterisation of a new, potentially photosensitive cell type in the inner retina of rodents and humans. These cells contain cone opsin photopigments and other functional makers of cone photoreceptors, however, they are located in the inner retina, adjacent to ganglion cells, but lack the distinctive cone photoreceptor morphology.
Showing behaviourally that aged mice lacking rods and cones that have undergone severe transneuronal degeneration are still capable of responding to environmental irradiance.
Demonstrating that the most recently discovered functional mammalian photopigment, melanopsin is maintained in the rd/rd cl and that indeed the melanopsin positive ganglion cells are activated in response to light.
Isolation and sequencing of a mammalian orthologue of melanopsin.
Isolation and sequencing of the RH2 cone opsin pigment from Anguilla anguilla.
- Anthony Vugler, Jean Lawrence, James Walsh, Amanda Carr, Carlos Gias, Ma’ayan Semo, Ahmad Ahmado, Lyndon da Cruz, Peter Andrews, Peter Coffey (2007). Embryonic stem cells and retinal repair. Mechanisms of Development 124, 807–829.
- Semo, M., Vugler, A.A. & Jeffery, G. (2007) Paradoxical opsin expressing cells in the inner retina that are augmented following retinal degeneration. Eur J Neurosci, 25, 2296-2306
- Semo, M., Llamosas M.M., Foster, R.G. & Jeffery, G. (2005) Melanopsin (Opn4) positive cells in the cat retina are randomly distributed across the ganglion cell layer. Vis Neurosci, 22, 111-116
- Semo, M., Lupi, D., Peirson, S.N., Butler, J.N. & Foster, R.G. (2003) Light-induced c-fos in melanopsin retinal ganglion cells of young and aged rodless/coneless (rd/rd cl) mice. Eur J Neurosci, 18, 3007-3017.
- Semo, M., Peirson, S., Lupi, D., Lucas, R.J., Jeffery, G. & Foster, R.G. (2003) Melanopsin retinal ganglion cells and the maintenance of circadian and pupillary responses to light in aged rodless/coneless (rd/rd cl) mice. Eur J Neurosci, 17, 1793-1801.