Three novel human VMD2-like genes are members of the evolutionary highly conserved RFP-TM family

Area of Science:

• Genetics
• Molecular Biology
• Human Physiology

Background:

• The RFP-TM protein family, characterized by a conserved domain and RFP motif, includes VMD2, the gene implicated in Best disease.
• Mutations in the VMD2 gene's N-terminal RFP-TM domain are strongly associated with disease, highlighting its functional importance.

Purpose of the Study:

• To identify and characterize novel human genes belonging to the RFP-TM protein family.
• To investigate the chromosomal localization and tissue-specific expression of these newly identified genes.

Main Methods:

• Gene identification and sequence analysis focusing on conserved RFP-TM domains.
• Fluorescence In Situ Hybridization (FISH) for chromosomal localization.
• Reverse Transcription Polymerase Chain Reaction (RT-PCR) for gene expression analysis.

Main Results:

• Three novel VMD2-related human genes, VMD2L1, VMD2L2, and VMD2L3, were identified.
• These genes share conserved RFP-TM domains but possess unique C-termini.
• FISH analysis mapped VMD2L1 to chromosome 19p13.2-p13.12, VMD2L2 to 1p32.3-p33, and VMD2L3 to 12q14.2-q15.
• RT-PCR revealed tissue-restricted expression: VMD2L1 and VMD2L2 are abundant in the colon, VMD2L1 in the retinal pigment epithelium, and VMD2L3 in skeletal muscle.

Conclusions:

• The discovery of VMD2L1-3 expands the human RFP-TM protein family.
• The conserved RFP-TM domains suggest a shared functional role, while unique C-termini may confer distinct functions.
• Tissue-specific expression patterns indicate specialized roles for these proteins in different human tissues, including the colon, retina, and skeletal muscle.