A typology of photoreceptor gene expression patterns in the mouse.
Mutations in photoreceptor-enriched genes have been implicated in dozens of human retinal diseases, yet no systematic analysis of rod and cone gene expression patterns has been carried out. In addition, although cone photoreceptor loss accounts for much of the morbidity of retinal disease, relatively few cone-specific genes are known. In this study, we carried out microarray and in situ hybridization analyses of the mouse Neural retina leucine zipper gene (Nrl) mutant, which shows an en masse conversion of rods into cones, to establish a typology of photoreceptor gene expression and to identify novel cone-specific genes. We found a total of 18 new cone-enriched genes, some of which map near uncloned retinal disease loci. Several of these genes have a dorsal-ventral (D-V) pattern of expression similar to that of short- or medium-wavelength opsins. We carried out microarray analysis of dorsal and ventral microdissected WT retina and found additional photoreceptor genes with an asymmetric distribution. Overall, we found that photoreceptor genes fall on an expression spectrum from rod-specific to cone-specific, with many showing varying degrees of rod and cone coexpression. These expression patterns can be reliably predicted from microarray data alone. Our results demonstrate definitive molecular differences between rods and cones that may underlie the physiological differences between these two classes of photoreceptors.
Corbo
Joseph C
JC
Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Myers
Connie A
CA
Lawrence
Karen A
KA
Jadhav
Ashutosh P
AP
Cepko
Constance L
CL
D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors / Q000378:metabolism; D019521:Body Patterning / Q000235:genetics; D005136:Eye Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D051379:Mice; D008810:Mice, Inbred C57BL; D020411:Oligonucleotide Array Sequence Analysis; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology / Q000378:metabolism*; D017948:Retinal Rod Photoreceptor Cells / Q000166:cytology / Q000378:metabolism*
D050976:Basic-Leucine Zipper Transcription Factors; D005136:Eye Proteins; C084884:Nrl protein, mouse