Abstract
Purpose :
Retinal ganglion cells (RGCs) are the cells that send visual information to the brain, and encompass a diverse set of functional and molecular cell types. One subgroup of RGCs, known as direction selective retinal ganglion cells (DS RGCs), responds preferentially to a particular direction of motion, yet still show a variety of functional and molecular identities. For example, the transcription factors Satb1 and Satb2 are expressed in the majority of mouse DS RGCs. Our aim is to determine if these transcription factors are required for the development of the direction-selective responses in the mouse retina.
Methods :
Breeding Satb1-floxed and Satb2-floxed mice to a Pax6-CRE mouse produced double knockout mice with the genes knocked out in the far peripheral nasal and temporal retina. Spiking activity of RGCs within these retinal areas was recorded in-vitro on a planar 512-electrode array. DS RGCs were identified based on their responses to a full field drifting gratings of various direction and spatial and temporal periods. DS RGCs were classified into ON and ON/OFF types using their spatio-temporal tuning. After recording, the retinas were immunostained to test if the recorded area was CRE positive and lacked Satb1/2 expression.
Results :
We found that the number of the detected ON DS cells was unchanged between the KO and litter mate control animals. At the same time, significantly smaller number of ON/OFF DS RGCs was detected in the KO. Furthermore, out of the four ON/OFF DSRGC types selective for the four cardinal directions of motion, the one selective for the upward motion was affected the least.
Conclusions :
Satb1/2 transcription factor is required for the correct development of the ON/OFF direction selective pathways in the retina. Further studies are needed to determine the individual roles of the two transcription factors and to test if they play a role in maintenance of the DSRGCs.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.