Can I pack chromatin in a test tube?
This depends a little bit on what you mean by metaphase configuration. I would distinguish between a couple different things going on there. First, you have chromosome condensation (going from lots of floppy DNA to tightly coiled DNA). Second, you have sister chromatid pairing (giving you those nice X-shaped chromosomes). Third you have alignment of the chromosomes at the metaphase plate. A lot of work has been done on reconstituting parts of the cell cycle in extract systems. You can certainly recapitulate chromosome condensation in extracts – see for instance this paper. You can make pretty decent spindles in Xenopus extracts, but they don’t seem to make really pretty paired chromosomes and a nice metaphase plate the way cells do – see figure 1 of this News and Views. Also, what’s in the test tube in the case of these extract systems is a really com
