The cDNA sequence of horse transferrin.

The research article examines the cDNA sequence of horse transferrin, a protein involved in iron transportation, which was determined through sequencing from a horse liver cDNA library and PCR-derived clones. The cDNA sequence shares 80% sequence identity with human transferrin cDNA and encodes a protein of 706 residues, retaining the typical transferrin family traits, such as a duplicated structure, iron binding, and conserved cysteine residues.

Methodology and Results

• The researchers extracted the cDNA sequence of horse transferrin by sequencing clones they isolated from a horse liver cDNA library and additional clones they obtained through Polymerase Chain Reaction (PCR). Here, the cDNA library represents a collection of genetic information of horse liver cells encoded in complementary DNA (cDNA).
• The sequence, spread over 2305 base pairs (bp), included part of the 5′ untranslated region and extended to the poly(A) tail, which are essential features of a mature mRNA molecule. The 5′ untranslated region serves vital regulatory functions, while the polyA tail protects mRNA from degradation and aids in transportation.

Comparison with Human Transferrin cDNA

• The extracted horse transferrin cDNA sequence exhibited an 80% sequence identity with the human transferrin cDNA. This significant overlap indicates a marked genetic similarity between horse and human transferrin and could underpin similarities in function and structure between the two species.
• The cDNA sequence of horse transferrin encoded a protein of 706 residues, including a signal sequence of 19 amino acids. Signal sequences are short peptide chains that direct the transportation of the protein within or outside the cell.

Characteristic Transferrin Features

• The horse transferrin cDNA sequence displayed significant features characteristic of the transferrin family. It had a duplicated structure, which implies the presence of repeated segments in the sequence.
• It also contained conserved iron binding sites and cysteine residues. Transferrins act as iron-chelating proteins, hence, these iron binding sites are crucial for the protein’s function. Meanwhile, the cysteine residues are actively involved in the formation of disulfide bridges contributing to the three-dimensional structure of the protein.