In order to compare the transcriptome of S- and M-cones, we need to isolate true S-cones. An existing transgenic mouse line that expresses EGFP driven by an S-opsin promoter was deemed unreliable, because some S-opsin negative cones also express GFP. This is likely due to the short S-opsin promoter region used in generating the mouse line. Due to the low percentage of true S-cones, this contamination from M-cones precludes successful RNAseq. In the past year, we have generated a mouse line using Bacterial Artificial Chromosome (BAC) recombination to include longer upstream and downstream regulatory sequences at the endogenous S-opsin gene locus. We successfully screened several mouse lines that express yellow fluorescent protein YFP (Venus) only in S-opsin expressing cones. We have used fluorescent sorting methods to acquire true S-cones from the dorsal retina and to prepare samples for gene profiling experiments. Part of this data has been used in a collaborative project with Anand Swaroops lab, who studies the development and evolutionary origin of rods. We will compare RNAseq data from S-cones and M-cones and identify candidate genes for their synaptic targeting. In parallel, we are developing a single cell based technique to manually pick individual photoreceptors from dissociated retinal tissues. Additionally, we have successfully labeled live S-cones in the ground squirrel retina and have been able to pick them individually. This will allow us to genetically profile S-cones and M-cones from the ground squirrel retina, which has complete separate S- and M-cone systems.
| Kiser, Philip D; Zhang, Jianye; Sharma, Aditya et al. (2018) Retinoid isomerase inhibitors impair but do not block mammalian cone photoreceptor function. J Gen Physiol 150:571-590 |
| Fan, Jianguo; Jia, Li; Li, Yan et al. (2017) Maturation arrest in early postnatal sensory receptors by deletion of the miR-183/96/182 cluster in mouse. Proc Natl Acad Sci U S A 114:E4271-E4280 |
| Kim, Jung-Woong; Yang, Hyun-Jin; Oel, Adam Phillip et al. (2016) Recruitment of Rod Photoreceptors from Short-Wavelength-Sensitive Cones during the Evolution of Nocturnal Vision in Mammals. Dev Cell 37:520-32 |
| Miyagishima, Kiyoharu J; Grunert, Ulrike; Li, Wei (2014) Processing of S-cone signals in the inner plexiform layer of the mammalian retina. Vis Neurosci 31:153-63 |
