title: Transgenic mice expressing Cre-recombinase specifically in M- or S-cone photoreceptors.
abstract: OBJECTIVE
  To establish lines of transgenic mice that express Cre-recombinase in M- or S-cone photoreceptors for generating cone photoreceptor-specific (conditional) mutants.
  
  
  METHODS
  Five kilobases of 5' upstream sequence of the mouse red-green (M) opsin gene or 0.5 kb of the mouse blue (S) opsin gene was cloned into a Cre-expression plasmid. Transgenic mice were generated and characterized, and appropriate lines were established. The Cre-transgenic mice were crossed with ROSA26-lacZ mice (containing floxed beta-galactosidase gene) and analyzed to determine Cre-recombinase activity.
  
  
  RESULTS
  Immunofluorescence study showed successful targeting of Cre-recombinase expression to cone photoreceptors. Double staining with anti-Cre antibody and anti-M- or anti-S-opsin antibody revealed specificity of Cre expression in M-opsin- and/or S-opsin-positive photoreceptors. Mating with ROSA26-lacZ mice demonstrated that Cre-recombinase was functionally active in M- or S-cones.
  
  
  CONCLUSIONS
  Lines of transgenic mice that specifically express functional Cre-recombinase in M- or S-cones were established in this study. Because mutations in several widely expressed genes lead to photoreceptor degeneration, these transgenic mice should be valuable in generating conditional mutants to investigate the function of various genes specifically in cone photoreceptors.
authors.affiliation: Department of Ophthalmology, the W. K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan 48105, USA.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Akimoto
authors.forename: Elena
authors.initials: E
authors.lastname: Filippova
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Gage
authors.forename: Xuemei
authors.initials: X
authors.lastname: Zhu
authors.forename: Cheryl M
authors.initials: CM
authors.lastname: Craft
authors.forename: Anand
authors.initials: A
authors.lastname: Swaroop
mesh_terms: D000818:Animals; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D005822:Genetic Vectors; D019426:Integrases / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D010957:Plasmids; D017949:Retinal Cone Photoreceptor Cells / Q000201:enzymology*; D017299:Rod Opsins / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D017299:Rod Opsins; D014764:Viral Proteins; C095855:long-wavelength opsin; C095854:middle-wavelength opsin; C095853:short-wavelength opsin; C045073:Cre recombinase; D019426:Integrases; D001616:beta-Galactosidase