Isolation of the mouse nyctalopin gene nyx and expression studies in mouse and rat retina
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Katrin Pesch1, Christina Zeitz, Julia E Fries
1Molekulargenetisches Labor, Universitäts-Augenklinik Tübingen, Germany.
Purpose:
It has been shown recently that mutations in NYX (nyctalopin on chromosome X), encoding a novel protein associated with the leucine-rich repeat (LRR) protein superfamily, are responsible for the complete form of X-linked congenital stationary night blindness (CSNB1). This study describes the isolation and molecular characterization of the mouse orthologue Nyx and its expression pattern in the retina.
Methods:
Nyx was isolated by conventional DNA library screening and polymerase chain reaction (PCR)-based approaches. Gene expression in different mouse tissues was studied by RT-PCR. Subsequently, the expression pattern of Nyx and its gene product in mouse and rat retinas was investigated by RNA in situ hybridization and immunohistochemistry with Nyx-specific antibodies.
Results:
The Nyx gene encodes a protein of 476 amino acids that contain 11 consecutive LRR motifs flanked by amino- and carboxyl-terminal cysteine-rich LRRs. At the amino acid level, Nyx is highly homologous to its human orthologue (86% identity). The gene is expressed in the eye but also, at lower levels, in brain, lung, spleen, and testis. Nyx expression was found during all stages of postnatal retinal development and was confined to cells of the inner nuclear layer and the ganglion cell layer in adult mouse and rat retinas.
Conclusions:
These data suggest an important function of the Nyx protein in the inner retina and provide evidence that CSNB1 is based on a defect in the inner retinal circuitry.
Insights
Mutations in the NYX gene cause X-linked congenital stationary night blindness (CSNB1). This study isolated the mouse Nyx gene and found its expression in the inner retina, suggesting a role in visual circuitry.
Area of Science:
- Genetics
- Neuroscience
- Ophthalmology
Background:
- Mutations in the NYX gene are linked to X-linked congenital stationary night blindness (CSNB1).
- NYX encodes nyctalopin, a protein in the leucine-rich repeat (LRR) superfamily.
- Understanding the mouse orthologue's function is crucial for CSNB1 research.
Purpose of the Study:
- Isolate and characterize the mouse Nyx gene.
- Determine the expression pattern of Nyx in the retina.
- Investigate the role of Nyx in retinal development and function.
Main Methods:
- DNA library screening and PCR for Nyx isolation.
- RT-PCR to study gene expression in various tissues.
- RNA in situ hybridization and immunohistochemistry for retinal expression analysis.
Main Results:
- The mouse Nyx gene encodes a 476-amino acid protein with LRR motifs, highly homologous to human NYX.
- Nyx is expressed in the eye, brain, lung, spleen, and testis.
- Nyx expression occurs throughout postnatal retinal development, localized to the inner nuclear and ganglion cell layers.
Conclusions:
- Nyx protein plays a significant role in the inner retina.
- CSNB1 likely results from defects in the inner retinal circuitry.
- This research provides a foundation for understanding CSNB1 pathogenesis.
