A method for the selective irradiation of part of a genome.
We developed a method for partial irradiation of cell nuclei and for highlighting the irradiated chromatin domain(s) in both interphase nuclei and metaphase chromosomes. The method involves the use of the replication program of chromosomes and consists of three major steps: I) selection of a suitable chromatin domain, II) damage induction by 125I, and III) visualization of the domain. Here, the first step of the method, applied to Chinese hamster HA-1 cells, is described. Using pulse labelling with the replication marker IUdR, it was shown that Xq does not replicate at early S-phase and that the replication timing of Xq can be highly effectively synchronized with hydroxyurea in a whole cell population. Thus, the replication timing of Xq may be used to exclude or to incorporate 125I into the Xq. Other chromatin can be selected and targeted with 125I in a similar way. Examples of possible applications of the method are given.
Ludwików
G
G
Center for Microscopical Research, Department of Cell Biology and Histology, The AMC, University of Amsterdam, The Netherlands. G.Ludwikov@amc.uva.nl
Hoebe
R A
RA
Franken
N A
NA
van Oven
C H
CH
Stap
J
J
Aten
J A
JA
D000818:Animals; D018929:Cell Culture Techniques; D002453:Cell Cycle; D002467:Cell Nucleus / Q000235:genetics*; D002843:Chromatin / Q000528:radiation effects*; D006224:Cricetinae; D004249:DNA Damage / Q000235:genetics / Q000528:radiation effects*; D006918:Hydroxyurea / Q000008:administration & dosage; D007065:Idoxuridine / Q000008:administration & dosage; D007150:Immunohistochemistry; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000494:pharmacology*; D019384:Nucleic Acid Synthesis Inhibitors / Q000008:administration & dosage; D011878:Radiotherapy / Q000379:methods / Q000639:trends
D002843:Chromatin; D007457:Iodine Radioisotopes; D019384:Nucleic Acid Synthesis Inhibitors; D007065:Idoxuridine; D006918:Hydroxyurea