CLONING OF EQUINE INTERLEUKIN-1-ALPHA AND EQUINE INTERLEUKIN-1-BETA AND DETERMINATION OF THEIR FULL-LENGTH CDNA SEQUENCES

Objectives-To clone equine interleukin 1 alpha (IL-1 alpha) and equine interleukin 1 beta (IL-1 beta) and determine their full-length cDNA s equences. Procedure-The mRNA isolated from lipopolysaccharide-stimulat ed cultured equine monocytes was reverse transcribed, and a cDNA libra ry was constructed in a lambda phage. The cDNA library was screened by means of plaque hybridization with radiolabeled human IL-1 alpha and IL-1 beta cDNA probes. The cDNA nucleotide sequences for equine IL-1 a lpha and equine IL-1 beta were determined by use of the dideoxy chain termination technique. The cDNA sequences were analyzed, using compute r software, for sequence characteristics and compared with sequences r eported for other species. Results-The cDNA for equine IL-1 alpha was 1,728 base pairs in length with an ORF encoding a peptide of 270 amino acids with a predicted molecular mass of 30.823 kd. The cDNA for equi ne IL-1 beta was 1,473 base pairs in length with an ORF encoding a pep tide of 268 amino acids with a predicted molecular mass of 30.342 kd. Similarity between amino acid sequence of equine IL-1 alpha and sequen ces for IL-1 alpha of other species ranged from 62.5 to 82.2%; similar ity between amino acid sequence of equine IL-1 beta and sequences for IL-1 beta of other species ranged from 62.5 to 66.4%. Similarity betwe en amino acid sequences of equine IL-1 alpha and equine IL-1 beta was 26%. Conclusions and Clinical Relevance-Results establish a basis for studying the roles of interleukin 1 in healthy and diseased joints in horses.