SUBCELLULAR-LOCALIZATION, DISTRIBUTION AND EXPRESSION OF CALMODULIN IN ZEA-MAYS ROOTS

The subcellular localization, distribution and the steady state level of calmodulin from maize roots (Zea mays L., cv. LG 11) were studied. To analyze the subcellular localization, 2-day old root membranes were fractionated by sucrose density gradient centrifugation and immunoblo tting was done with an antibody raised against a vertebrate calmodulin (SWant) which recognized the plant calmodulin. Calmodulin was princip ally associated with high density fractions and particularly plasmalem ma. For studying the distribution of calmodulin in various zones of Ze a mays roots, a micro method of membrane preparation was developed. Mo st of the calmodulin was present in microsomes isolated from the root apex corresponding to the first 4 mm of a 15 +/- 2 mm root. An identic al distribution was found by studying the steady state level of the pr otein by Northern blotting using a cDNA clone of Zea mays calmodulin.