Alkaline Phosphatase Activity and Chromosome Variation in Human Cells in Culture

Abstract

A detailed chromosomal analysis of a heteroploid strain of human cultured cells with very high alkaline phosphatase activity and of enzyme-deficient lines derived from the same strain indicates that the reduction in enzyme activity may be associated with a loss of 7 to 8 chromosomes. Furthermore, the chromosome losses in the deficient lines were not distributed randomly over the various groups, but were most pronounced in groups IV (long acrocentrics) and VII (short acrocentrics). Group VII showed the greatest loss: The chromosome number was at least halved with respect to the parental strain. However, the differences in specific alkaline phosphatase activities between the parental strain and the deficient lines were nearly 1000-fold. Therefore, there apparently is no linearity between alkaline phosphatase activity and chromosomal dose in these cells. The present findings agree with the claim that short acrocentric chromosomes may be carriers of genes controlling alkaline phosphatase activity in human cells.