title: Identification of differentially expressed genes in carp rods and cones.
abstract: OBJECTIVE
  Rods and cones differ in their photoresponse characteristics, morphology, and susceptibilities to certain diseases. To contribute to the studies at the molecular level of these differences, we tried to identify genes expressed preferentially in rods or cones.
  
  
  METHODS
  From purified carp rods and cones, we extracted their RNA and obtained corresponding cDNA pools (rod cDNA and cone cDNA). We employed the suppression subtractive hybridization method to identify the genes expressed preferentially in rods or cones. Cone cDNA was subtracted from rod cDNA to obtain cDNA, which ideally contained cDNA expressed preferentially in rods (R/c cDNA). Similarly, rod cDNA was subtracted from cone cDNA to obtain C/r cDNA. With differential array screening, we screened candidate genes that were expressed mainly or exclusively in rods or cones. The nucleotide sequences of the positive genes were determined. In some of them, their mRNA localizations were confirmed by in situ hybridization.
  
  
  RESULTS
  R/c cDNA contained genes already known to code rod specific proteins, such as cGMP gated channel, transducin beta1, and rhodopsin. In sharp contrast, C/r cDNA contained genes that code proteins of which functions are mostly unknown. Among them, N-myc downregulated gene 1-like (NDRG1L) and aryl hydrocarbon receptor 2 (AhR2) were most abundant, and by in situ hybridization, they were proven to be expressed specifically in cones.
  
  
  CONCLUSIONS
  Using purified rods and cones, we identified mRNAs expressed preferentially in rods or cones. Of particular interest is the specific expression of NDRG1L and AhR2 in cones.
authors.affiliation: Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Shimauchi-Matsukawa
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Aman
authors.forename: Shuji
authors.initials: S
authors.lastname: Tachibanaki
authors.forename: Satoru
authors.initials: S
authors.lastname: Kawamura
mesh_terms: D000222:Adaptation, Physiological / Q000528:radiation effects; D000818:Animals; D002347:Carps / Q000235:genetics*; D002999:Clone Cells; D018076:DNA, Complementary / Q000235:genetics; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000528:radiation effects; D017403:In Situ Hybridization; D008027:Light; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects; D017948:Retinal Rod Photoreceptor Cells / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects; D017299:Rod Opsins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D017299:Rod Opsins