Prolonged dark adaptation changes connexin expression in the mouse retina.
In the retina, ambient light levels influence the cell coupling provided by gap junction (GJ) channels, to compensate the visual function for various lighting conditions. However, the effects of ambient light levels on expression of connexins (Cx), the proteins that form the GJ channels, are poorly understood. In the present study, we first determined whether gene expression of specific Cx (Cx26, Cx31.1, Cx36, Cx37, Cx40, Cx43, Cx45, Cx50, and Cx57) was affected by prolonged dark adaptation. Cx mRNA relative levels were determined in mouse retinas dark adapted for 3 hr, 1 day, and 7 days by using quantitative real-time PCR. Transcript levels of some Cx were repressed after 3 hr (Cx57), 1 day (Cx45), or 7 days (Cx36 and Cx43) of dark adaptation; others were increased after 1 day (Cx50) or 7 days (Cx31.1 and Cx37); and two of them (Cx26 and Cx40) were not significantly altered. The second aim was to determine whether prolonged dark adaptation affects protein expression of two important Cx in retina: neuronal Cx36 and glial Cx43. We were able to demonstrate that important changes in protein distribution and expression also took place in retina during long-term dark adaptation. Given their localization, the specific alterations in Cx expression may reflect their distinct response to ambient light levels.
Department of Physiology and Biophysics, Institute of Biomedical Sciences,University of São Paulo, São Paulo, SP, Brazil. kihara@icb.usp.br
Alexandre Hiroaki
AH
Kihara
Leandro Mantovani
LM
de Castro
Anselmo Sigari
AS
Moriscot
Dânia Emi
DE
Hamassaki
D000818:Animals; D002450:Cell Communication / Q000502:physiology; D018031:Connexin 43 / Q000235:genetics / Q000378:metabolism; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D003623:Dark Adaptation / Q000502:physiology*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D017629:Gap Junctions / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D008027:Light; D051379:Mice; D008810:Mice, Inbred C57BL; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D010775:Photic Stimulation; D012160:Retina / Q000378:metabolism*; D014785:Vision, Ocular / Q000502:physiology; D000097004:Gap Junction delta-2 Protein
D018031:Connexin 43; D017630:Connexins; D005136:Eye Proteins; D000097004:Gap Junction delta-2 Protein