title: Exaggerated eye growth in IRBP-deficient mice in early development.
abstract: OBJECTIVE
  Because interphotoreceptor retinoid-binding protein (IRBP) is expressed before being needed in its presumptive role in the visual cycle, we tested whether it controls eye growth during development.
  
  
  METHODS
  The eyes of congenic IRBP knockout (KO) and C57BL/6J wild-type (WT) mice ranging in age from postnatal day (P)2 to P440 were compared by histology, laser micrometry, cycloplegic photorefractions, and partial coherence interferometry.
  
  
  RESULTS
  The size and weight of IRBP KO mouse eyes were greater than those of the WT mouse, even before eye-opening. Excessive ocular enlargement started between P7 and P10, with KO retinal arc lengths becoming greater compared with WT from P10 through P30 (18%; P < 0.01). The outer nuclear layer (ONL) of KO retinas became 20% thinner between P12 to P25, and progressed to 38% thinner at P30. At P30, there were 30% fewer cones per vertical section in KO than in WT retinas. Bromodeoxyuridine (BrdU) labeling indicated the same number of retinal cells were born in KO and WT mice. A spike in apoptosis was observed in KO outer nuclear layer at P25. These changes in size were accompanied by a large decrease in hyperopic refractive error, which reached -4.56 ± 0.70 diopters (D) versus +9.98 ± 0.993 D (mean ± SD) in WT, by postnatal day 60 (P60). CONCLUSIONS; In addition to its role in the visual cycle, IRBP is needed for normal eye development. How IRBP mediates ocular development is unknown.
authors.affiliation: Department of Ophthalmology, Emory University, Atlanta, Georgia 30322, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Wisard
authors.forename: Amanda
authors.initials: A
authors.lastname: Faulkner
authors.forename: Micah A
authors.initials: MA
authors.lastname: Chrenek
authors.forename: Timothy
authors.initials: T
authors.lastname: Waxweiler
authors.forename: Weston
authors.initials: W
authors.lastname: Waxweiler
authors.forename: Christy
authors.initials: C
authors.lastname: Donmoyer
authors.forename: Gregory I
authors.initials: GI
authors.lastname: Liou
authors.forename: Cheryl M
authors.initials: CM
authors.lastname: Craft
authors.forename: Gregor F
authors.initials: GF
authors.lastname: Schmid
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Boatright
authors.forename: Machelle T
authors.initials: MT
authors.lastname: Pardue
authors.forename: John M
authors.initials: JM
authors.lastname: Nickerson
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D005123:Eye / Q000033:anatomy & histology* / Q000254:growth & development*; D005124:Eye Abnormalities / Q000235:genetics* / Q000473:pathology*; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D008857:Microscopy, Interference; D009929:Organ Size / Q000502:physiology; D012030:Refractive Errors / Q000473:pathology; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology; D012177:Retinol-Binding Proteins / Q000172:deficiency / Q000235:genetics*; D016196:S Phase / Q000502:physiology; D000099214:Retinol-Binding Proteins, Interstitial
chemical_list: D005136:Eye Proteins; D012177:Retinol-Binding Proteins; D000099214:Retinol-Binding Proteins, Interstitial