Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Defective anion transport and marked spherocytosis with membrane instability caused by hereditary total deficiency of red cell band 3 in cattle due to a nonsense mutation.

Abstract

Cattle that showed moderate uncompensated anaemia with hereditary spherocytosis inherited in an autosomal incompletely dominant mode and retarded growth, were studied. SDS-PAGE, immunoblotting and electron microscope analysis by the freeze fracture method, showed that the erythrocytes of the proband lacked band 3 protein (anion exchanger 1, a transmembrane glycoprotein mediating Cl-/bicarbonate ion exchange) completely. Sequence analysis of band 3 cDNA and genomic DNA from the proband showed a C→T substitution resulting in a nonsense mutation (CGA→TGA; Arg→Stop) at the position corresponding to codon 646 in human erythrocyte band 3 cDNA. The erythrocytes of the proband were deficient in spectrin, ankyrin, actin and protein 4.2, resulting in a distorted and disrupted membrane skeletal network with decreased density. Thus, the erythrocyte membranes of the proband were extremely unstable and showed a reduced surface area in several ways, such as invagination, vesiculation and extrusion of microvesicles, leading to the formation of spherocytes. Total deficiency of band 3 also resulted in defective Cl-/bicarbonate ion exchange, causing mild acidosis with decreases in the bicarbonate concentration and total CO2 in the blood. The results show that band 3 contributes to red cell membrane stability, CO2 transport, and acid-base homeostasis, but is not always essential for the survival of cattle.