title: 5-Aminouracil treatment. A method for estimating G2.
abstract: Treatment of Vicia faba lateral roots with a range of concentrations of 5-aminouracil (5-AU) indicate that cells are stopped at a particular point in interphase. The timing of the fall in mitotic index suggests that cells are held at the S - G(2) transition. When cells are held at this point, treatments with 5-AU can be used to estimate the duration of G(2) + mitosis/2 of proliferating cells. Treatment with 5-AU can also be used to demonstrate the presence of subpopulations of dividing cells that differ in their G(2) duration. Using this method, 5-AU-induced inhibition, we have confirmed that in V. faba lateral roots there are two populations of dividing cells: (a) a fast-dividing population, which makes up approximately 85% of the proliferating cell population and has a G(2) + mitosis/2 duration of 3.3 hr, and (b) a slow-dividing population, which makes up approximately 15% of dividing cells and has a G(2) duration in excess of 12 hr. These estimates are similar to those obtained from percentage labeled mitosis (PLM) curves after incorporation of thymidine-(3)H.
mesh_terms: D008938:Mitosis / Q000187:drug effects*; D010944:Plants / Q000187:drug effects* / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors; D014316:Tritium; D014499:Uracil Mustard / Q000494:pharmacology*
chemical_list: D014316:Tritium; D013936:Thymidine; D014499:Uracil Mustard