Chicken antibodies to rabbit muscle actin with a restricted repertoire of F-actin recognition

Abstract

This report describes a polyclonal antibody against actin with unexpected and unusual properties. The antibody was raised in chicken immunized with a complex of DNase I and rabbit skeletal muscle actin, and purified from egg yolk by affinity chromatography. In Western blots, it reacted with alpha, beta and gamma isoforms of actin. In immunofluorescence and dot blot assays, however, it recognized selectively actin filaments in myofibrils, microvilli of brush border-type epithelium and the "comet tails" of the intracellular parasite Listeria monocytogenes, while it did not react with stress fibers and peripheral belts of fibroblasts and epithelial cells, respectively. This reactivity pattern is reminiscent of that previously described for a monoclonal mouse antibody raised against smooth muscle actin (Sawtell et al., Cell Motil. Cytoskel. 11, 318, 1988). The data presented in this study are consistent with the hypothesis that the chicken antibody recognizes an actin epitope/actin epitopes either accessible in only a subpopulation of microfilaments, or expressed only in a particular conformation of F-actin.