Assignment of interleukin-1 receptor, type I (IL1R1) to bovine chromosome band 11q12 by in situ hybridization.

Interleukin-1 (IL-1) is an inflammatory cytokine involved in inflammation and immune responses (Dinarello, 1988). The IL-1 family is complex, with three ligands (IL-1·, IL-1ß and the IL-1 receptor antagonist) and two receptors (type I, IL-1R1 and type II, IL-1R2). IL-1R1, present in low numbers on most cells, is the predominant receptor on T-cells and fibroblasts (Sims et al., 1988). IL-1R2 is mainly expressed in neutrophils, B cells and monocytes (McMahan et al., 1991). The human and murine IL-1 receptors are transcribed from separate genes and have been assigned to HSA2 and to MMU1, respectively (Copeland et al., 1991). The bovine IL-1 receptor subtypes have been mapped to BTA11 by linkage analysis (Yoo et al., 1994; Kappes et al., 1997). ZOO-FISH data (Solinas-Toldo et al., 1995) indicate that most of HSA 2q corresponds to BTA 2q12→q44. On the contrary, IL1B (HSA 2q14), is the first locus beyond a breakpoint proximal to PROC (HSA 2q13→ q14) that defines a region of synteny with BTA11 (Lopez-Corrales et al., 1998). Our data assign IL1R1 to BTA 11q12, at a greater distance from IL1B (BTA 11q21→q23) compared to man where the genes are placed in the same chromosomal subregion (HSA 2q12 and 2q14 respectively). Fig. 1. Chromosomal localisation of the bovine IL-1R1 gene. (a) Partial metaphase spread showing a typical FISH with the IL1R1 probe on BTA 11q12. (b) Ideogram of BTA11 showing the position of IL1R1.