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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A049
A cell clone displaying a localization of an amplified sequence to the axis
of metaphase and early anaphase chromatids is described. The amplified, GFP
labeled sequences form a line along the axis of the daughter chromatids,
with the measured diameter of the GFP-signal close to the resolution limit
of the light microscope and roughly ¢ the chromatid diameter. The gene
amplified chromosome region contains vector insertion sites with lac operator
repeats which were detected by a lac-repressor-GFP fusion protein
(Robinett et al., 1996, J. Cell Biol.135:1685; Li et al., 1998, J. Cell Biol.
140:975). Within interphase nuclei, these integration sites can be detected
as a number of GFP-fluorescent dots, restricted to one or two areas in the
nucleus, corresponding to individual chromosomes carrying the sequences.
The tagged sequences are located at the periphery of condensing prophase
chromatids and do not move to the axial position until the prophase/metaphase
transition. Live cell observation showed that the linear alignment is lost
early in G1. Our results will be compared to existing models of mitotic
chromosome organization.
REPRODUCIBLE FOLDING OF AN AMPLIFIED DNA SEQUENCE TO THE METAPHASE CHROMATID
AXIS
Dietzel S, Belmont AS
University of Illinois at Urbana-Champaign, Cell and Structural Biology,
Urbana, Illinois, USA