Spatial and temporal expression of MFRP and its interaction with CTRP5

Area of Science:

• Ophthalmology
• Genetics
• Molecular Biology

Background:

• Mutations in the membrane frizzled-related protein (MFRP) gene are linked to nanophthalmos in humans.
• A splice site mutation in MFRP causes retinal degeneration in the rd6 mouse model.
• The MFRP gene is located near the CTRP5 gene, which is implicated in retinal degeneration and abnormal lens zonules.

Purpose of the Study:

• To characterize the spatial and temporal expression of the mouse Mfrp gene.
• To determine the tissue and subcellular localization of the MFRP protein.
• To investigate the interaction between MFRP and CTRP5.

Main Methods:

• Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for gene expression analysis.
• Western blot, immunohistochemistry, and immunoelectron microscopy for protein localization.
• Co-immunoprecipitation and immunoblot analysis to study protein interactions in ocular tissues and a heterologous system.

Main Results:

• Mfrp gene expression is specific to the retinal pigmented epithelium (RPE) and ciliary body (CB), beginning in early embryogenesis.
• MFRP protein localizes to the apical and basal membranes of RPE and ciliary epithelium (CE).
• MFRP and CTRP5 colocalize in RPE, CE, and MDCK cells, and they interact in ocular tissues and a heterologous system.

Conclusions:

• MFRP localizes to the plasma membrane of CE and RPE.
• MFRP colocalizes and interacts with CTRP5.
• These findings indicate a functional relationship between MFRP and CTRP5 in ocular tissues.