Two canine CD1a proteins are differentially expressed in skin

Area of Science:

• Immunology
• Genomics
• Comparative Biology

Background:

• Lipid antigen presentation to T cells is mediated by CD1 proteins.
• Understanding the CD1 locus is crucial for studying immune responses in different species.

Purpose of the Study:

• To characterize the complete CD1 locus in dogs (Canis familiaris).
• To investigate the expression, transcription, and structural features of canine CD1 proteins.

Main Methods:

• Analysis of the canine CD1 locus on chromosome 38.
• In vivo expression studies using anti-CD1 monoclonal antibodies (mAbs).
• Differential transcription analysis in canine tissues.
• Protein modeling and sequence alignment.
• cDNA sequencing and expressed sequence tag analysis.

Main Results:

• The canine CD1 locus contains eight CD1A genes (five pseudogenes), one canCD1B, one canCD1C, one canCD1D, and one canCD1E gene.
• In vivo expression confirmed for canCD1a6, canCD1a8, and canCD1b.
• Differential transcription of canCD1A genes observed, with higher canCD1A8 than canCD1A6 in skin.
• Canine CD1a proteins predicted to bind different glycolipids.
• Unique presence of three cytoplasmic tail variants (4, 15, and 31 amino acids) encoded by canCD1A genes.

Conclusions:

• The dog CD1 locus is complex, with multiple CD1A genes and pseudogenes.
• Canine CD1 proteins exhibit differential expression and unique structural features, including variable cytoplasmic tails.
• These findings provide insights into the evolution and function of the CD1 system in dogs.