Exogenous Deoxyribonucleoside Triphosphates II. Their Effect on Pulverized Human Chromosomes at the S Phase 1

Abstract

Summary

Sixteen peripheral blood leukocyte cultures were made from a patient with pulverized chromosomes. To 15 of his cultures, different and combinations of different deoxyribonucleotides were added 24 hr (S phase) before termination of the cultures. No deoxyribonucleotide was added to the sixteenth culture (experimental control). Seventy-nine of the one-hundred metaphases from the experimental control and 217 of the 1500 metaphases from the experimental cultures were pulverized. Most pulverized chromosomes in the experimental cultures belonged to two cultures. The nucleotides added were dATP and dCTP in one and dGTP and TTP in the other. The mitotic rates were within normal range in all cultures. This S phase experiment confirmed our G₂ phase experiment in that exogenous deoxyribonucleoside triphosphates can restore pulverized chromosomes. However, in two S phase experimental cultures, further pulverization was seen. This is thought to be due to the imbalance of the metabolic end-products of these nucleosides.