THE IL-1-ALPHA-GENE AND IL-1-BETA-GENE ARE CLOSELY LINKED (LESS-THAN 70 KB) ON MOUSE CHROMOSOME-2

The murine IL-1-alpha and IL-1-beta genes encode structurally and evolutionarily related cytokines that exert a regulatory role in numerous physiological processes including hemopoiesis. Previous studies have shown these genes to be closely linked in the F region of mouse chromosome 2. Here we show, using pulsed-field gel electrophoresis, that the IL-1-alpha and beta-genes of the CBA/H mouse are very closely linked and contained within a SmaI genomic fragment of approximately-70 kb. From conventional and PFGE analyses we suggest that IL-1-beta lies 5' to IL-1-alpha and that the two genes are in the same orientation and separated by approximately-50 kb. The apparent clustering of such hemopoietic genes is discussed in relation to evolutionary tandem gene duplication and possible associations with chromosomal fragile sites and leukemogenesis.