Expressed gene sequences of two variants of sheep interleukin-25

This report describes the cloning and characterization of sheep interleukin-25 (IL25) expressed gene sequences and shows that, like humans, sheep express two transcript variants of IL25. Transcript variant 1 (IL25v1) has a 510 bp open reading frame encoding a 169 amino acid polypeptide with a calculated Mr 19,200. The 498 bp IL25v2 encodes a 165 amino acid polypeptide with a calculated Mr 18,710; both with an isoelectric point equal to 8.0307. The additional 12 bp of IL-25 isoform 1 are at the 5′ end and encode an MYQA peptide, otherwise their sequences are identical. Phylogenetic analysis shows that both sheep IL-25 isoforms are most closely related to cattle and pig IL-25.