Intestinal Content of the Copper-Binding Protein in Brindled, Blotchy and Crinkled Mice and Cellular Copper Transport

Abstract

The copper-binding protein (CuBP) content of the proximal intestine of mutant mice and their age-matched litter mate controls was evaluated by means of an equilibrated chromatographic column procedure. Brindled (Mo^br) mice exhibited higher CuBP content when very young (2-3 days); thereafter their CuBP dropped below that of the controls, perhaps because of diminished growth and development prior to death at 11 days. Blotchy (Mo^b1) mice also exhibited higher CuBP levels at an early age (3–5 days). Over the next 6 days, CuBP levels were similar in the blotchy mutants and controls, and became higher in mutants 13–20 days old. In crinkled (cr/cr) mice, intestinal CuBP levels were higher at ages 8-9 and 16–17 days. This complicated developmental pattern was not matched by copper uptake as evaluated in isolated intestinal cells. Cellular copper uptake decreased with age in crinkled and control mice, with no significant differences between the two groups. Cells from brindled or blotchy mice also did not differ in copper uptake from that of their controls. It is concluded that CuBP plays no role in cellular copper uptake and is not a direct expression of the mottled gene.