Rr. Preston et C. Kung, ISOLATION AND CHARACTERIZATION OF PARAMECIUM MUTANTS DEFECTIVE IN THEIR RESPONSE TO MAGNESIUM, Genetics, 137(3), 1994, pp. 759-769
Four mutant strains of Paramecium tetraurelia with a reduced ability t
o respond behaviorally to Mg2+ have been isolated. Voltage-clamp analy
ses showed that their Mg2+ insensitivity is associated with a reduced
Ca2+-dependent Mg2+ current. The four mutants, which have been dubbed
''eccentric,'' result from recessive mutations in two unlinked loci, x
ntA and xntB. Further analysis of xntA(1) showed it to be unlinked to
any of the behavioral mutants of P. tetraurelia described previously,
but it is allelic to d4-521, a ''K+-resistant'' strain, and d4-596, a
''Ba2+-shy'' mutant. The varied pleiotropic effects of xntA(1), which
include increased resistance to Ni2+ and Zn2+ poisoning, suggest that
the locus encodes a central regulator of cell function in Paramecium.