RT Journal Article
SR Electronic
T1 Thyroid Hormone Controls Cone Opsin Expression in the Retina of Adult Rodents
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 4844
OP 4851
DO 10.1523/JNEUROSCI.6181-10.2011
VO 31
IS 13
A1 Anika Glaschke
A1 Jessica Weiland
A1 Domenico Del Turco
A1 Marianne Steiner
A1 Leo Peichl
A1 Martin Glösmann
YR 2011
UL http://www.jneurosci.org/content/31/13/4844.abstract
AB Mammalian retinas display an astonishing diversity in the spatial arrangement of their spectral cone photoreceptors, probably in adaptation to different visual environments. Opsin expression patterns like the dorsoventral gradients of short-wave-sensitive (S) and middle- to long-wave-sensitive (M) cone opsin found in many species are established early in development and thought to be stable thereafter throughout life. In mouse early development, thyroid hormone (TH), through its receptor TRβ2, is an important regulator of cone spectral identity. However, the role of TH in the maintenance of the mature cone photoreceptor pattern is unclear. We here show that TH also controls adult cone opsin expression. Methimazole-induced suppression of serum TH in adult mice and rats yielded no changes in cone numbers but reversibly altered cone patterns by activating the expression of S-cone opsin and repressing the expression of M-cone opsin. Furthermore, treatment of athyroid Pax8−/− mice with TH restored a wild-type pattern of cone opsin expression that reverted back to the mutant S-opsin-dominated pattern after termination of treatment. No evidence for cone death or the generation of new cones from retinal progenitors was found in retinas that shifted opsin expression patterns. Together, this suggests that opsin expression in terminally differentiated mammalian cones remains subject to control by TH, a finding that is in contradiction to previous work and challenges the current view that opsin identity in mature mammalian cones is fixed by permanent gene silencing.