Nrl is required for rod photoreceptor development.
The protein neural retina leucine zipper (Nrl) is a basic motif-leucine zipper transcription factor that is preferentially expressed in rod photoreceptors. It acts synergistically with Crx to regulate rhodopsin transcription. Missense mutations in human NRL have been associated with autosomal dominant retinitis pigmentosa. Here we report that deletion of Nrl in mice results in the complete loss of rod function and super-normal cone function, mediated by S cones. The photoreceptors in the Nrl-/- retina have cone-like nuclear morphology and short, sparse outer segments with abnormal disks. Analysis of retinal gene expression confirms the apparent functional transformation of rods into S cones in the Nrl-/- retina. On the basis of these findings, we postulate that Nrl acts as a 'molecular switch' during rod-cell development by directly modulating rod-specific genes while simultaneously inhibiting the S-cone pathway through the activation of Nr2e3.
Mears
A J
AJ
Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan 48105, USA.
Kondo
M
M
Swain
P K
PK
Takada
Y
Y
Bush
R A
RA
Saunders
T L
TL
Sieving
P A
PA
Swaroop
A
A
D000818:Animals; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D007150:Immunohistochemistry; D016350:Leucine Zippers; D051379:Mice; D017948:Retinal Rod Photoreceptor Cells / Q000254:growth & development*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D050976:Basic-Leucine Zipper Transcription Factors; D017931:DNA Primers; D004268:DNA-Binding Proteins; D005136:Eye Proteins; C490037:NRL protein, human; C084884:Nrl protein, mouse; D014157:Transcription Factors