Nucleotide and deduced amino acid sequence of equine retinal and pineal gland phosducin.

This research aimed to determine the full-length DNA sequence for a protein called phosducin (PHD) in horses and found high similarity with PHD sequences from other species. The results have implications for studying ocular inflammation in horses.

Methodology

• The study aimed to find the full-length complementary DNA (cDNA) sequence of the phosducin (PHD) in equine retinal and pineal gland cells.
• A primer set, a segment of short, single-stranded DNA which serves as the starting point for DNA synthesis, was designed to identify a fragment of the equine PHD nucleotide sequence. The sequence was derived from retinal RNA samples.
• The full-length cDNA was determined by a method called rapid amplification of cDNA ends (RACE).
• Newly designed primers were used for full-length cDNA. The nucleotide sequences were analyzed using computer software.
• The deduced amino acid sequence was compared with the sequences of PHD reported for other species. In addition, the sequence of equine pineal PHD was also cloned.

Results

• The cDNA nucleotide sequence for equine PHD was found to be 1,209 base pairs long, with an open-reading frame encoding a protein of 245 amino acids. This resulted in a calculated molecular mass of 28.214 kilodaltons (kd).
• When the sequence was compared with the amino acid sequences of PHD from other species, it showed 89 to 93% similarity, indicating a high degree of conservation between these proteins across species.
• The sequences of equine PHD from the retina and the pineal gland were found to be identical.
• The equine PHD contained a peptide sequence with 100% homology to an uveitopathogenic peptide reported for rat PHD.

Conclusion

• The PHD found in the horses is a highly conserved protein, meaning that its structure and function are preserved across different species.
• It shares a key segment with a strain found in rats that induces ocular inflammation, which could prove valuable in understanding diseases in horses’ eyes.
• The research provides a foundation for future studies into the role of PHD in ocular inflammation in horses.