DNase I sensitivity of Microtus agrestis active, inactive and reactivated X chromosomes in mouse-Microtus cell hybrids.
We isolated Microtus agrestis-mouse somatic cell hybrid clones which had retained either the active or the inactive M. agrestis X chromosome. In both hybrid clones the X chromosomes retained their original chromatin conformation as studied by the in situ nick translation technique--the active X chromosome retained its high sensitivity to DNase I while the inactive one remained insensitive. A clone in which the hypoxanthine guanine phosphoribosyltransferase (HPRT) gene had been spontaneously reactivated was isolated from the hybrid containing the inactive X chromosome. The in situ nick translation technique was used to study possible DNA conformation changes in the euchromatin of the inactive X chromosome with special reference to the reactivated HPRT locus. We found that the euchromatin in this X chromosome exhibited the same low sensitivity to DNase I as is characteristic of the inactive X chromosome.
Kerem
B S
BS
Department of Genetics, Hebrew University, Jerusalem, Israel.
Kottusch-Geiseler
V
V
Kalscheuer
V
V
Goitein
R
R
Sperling
K
K
Marcus
M
M
D000818:Animals; D003411:Arvicolinae / Q000235:genetics*; D002843:Chromatin / Q000187:drug effects / Q000648:ultrastructure; D003850:Deoxyribonuclease I / Q000494:pharmacology*; D004303:Dosage Compensation, Genetic; D022041:Euchromatin; D005260:Female; D006822:Hybrid Cells / Q000648:ultrastructure; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D051379:Mice; D014960:X Chromosome / Q000187:drug effects*
D002843:Chromatin; D022041:Euchromatin; D007041:Hypoxanthine Phosphoribosyltransferase; D003850:Deoxyribonuclease I