For two positively hybridizing BACs, EcoRI and HindIII shotgun libraries were constructed and screened. The cDNA insert was isolated, radiolabeled by the random-primed oligo-labeling method (Amersham Pharmacia Biotech, Piscataway, NJ), and hybridized to BAC clones encompassing the nob critical region. AI861796 GenBank is provided in the public domain by the National Center for Biotechnology Information, Bethesda, MD), containing a fragment of cDNA from the human NYX gene was obtained from the Image consortium provided in the public domain and hosted by The Lawrence Livermore National Laboratory, Livermore, CA). To isolate the murine nyx gene, a cDNA clone (GenBank accession no. All mice were phenotyped at 4 to 5 weeks of age, by using ERG, and were genotyped with various markers used for linkage analysis, as described previously. The F1 female carriers ( nob/+) were backcrossed to affected BALB/cByJ males, yielding 303 interspecific backcrossed mice. To increase the number of polymorphic markers that were informative for linkage analyses, we also used an interspecific cross in which BALB/cByJ nob/nob ( Mus musculus) females were mated to SPRET/Ei ( Mus spretus) males. A total of 469 mice from these intraspecific backcrossed mice were used in the linkage analysis. The F1 female offspring, who must be carriers for the nob mutation ( nob/+), were backcrossed to BALB/cByJ nob males. Affected BALB/cByJ nob males were crossed to normal C57BL/6J females. With the exception of nob mice, all other mouse strains were obtained from The Jackson Laboratory (Bar Harbor, ME). Intra- and interspecific breeding strategies were used to generate mouse pedigrees for linkage analyses. This model will be useful in defining the role of nyctalopin in signal transmission between photoreceptors and retinal bipolar cells.Īll procedures performed in animals were approved by the local institutional animal care and use committee and conformed to the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. The nob mouse is a model for human CSNB1. Behavioral testing shows that nob mice have a significant decrease in visual sensitivity.Ĭonclusions. The nyctalopin protein contains 11 leucine-rich repeats and is flanked by cysteine rich regions, which identifies it as a member of the small leucine rich proteoglycan family. Expression of nyx was most abundant in the retina and, in particular, in the inner nuclear layer. The nob phenotype is caused by an 85-bp deletion in the mouse nyx gene, which encodes the nyctalopin protein. Visual sensitivity was measured with an active avoidance behavioral test. The expression pattern of the nyx gene was examined with Northern blot analysis and in situ hybridization. Positional cloning, screening of candidate genes, and sequencing were used to identify the nob gene. The goals of the present study were to identify the nob gene defect, to characterize the expression pattern of the involved gene, and to assess visual sensitivity in nob mice. The available evidence indicates that the naturally occurring mouse mutant nob (no b-wave) provides an animal model for the complete form of human X-linked congenital stationary night blindness (CSNB1).
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