In somatic cells, the serine/threonine kinase Akt (or protein kinase B) was shown to contribute to processes linked to cellular growth, cell survival and cell cycle regulation. In contrast to these findings, the function of Akt during the meiosis of mammalian oocytes remains to be investigated. We analysed the phosphorylation pattern and the activity of Akt during meiotic maturation (transition...

Mitotic chromosomes are among the most recognizable structures in the cell, yet for over a century their internal organization remains largely unsolved. We applied chromosome conformation capture methods, 5C and Hi-C, across the cell cycle and revealed two distinct three-dimensional folding states of the human genome. We show that the highly compartmentalized and cell type-specific organization...

Surface topography of human metaphase chromosomes following GTG banding was examined using high resolution atomic force microscopy (AFM). Although using a completely different imaging mechanism, which is based on the mechanical interaction of a probe tip with the chromosome, the observed banding pattern is comparable to results from light microscopy and a karyotype of the AFM imaged metaphase s...

The position of an interchange quadrivalent at metaphase I of Allium triquetrum was modelled so as to simulate the original placement of the quadrivalent in the spindle and the preparation of linear spreads through squashing. In this way an expected distribution for the quadrivalent in linear spreads was generated. The procedure used polar views of metaphase I to which the quadrivalent was assi...

Several recent models for spindle length regulation propose an elastic pole to pole spindle matrix that is sufficiently strong to bear or antagonize forces generated by microtubules and microtubule motors. We tested this hypothesis using microneedles to skewer metaphase spindles in Xenopus laevis egg extracts. Microneedle tips inserted into a spindle just outside the metaphase plate resulted in...

The combination of multiple dye-DNA interactions, a fluorescence digital imaging system with a scientific CCD camera, and multivariate image analysis allows the rapid karyotyping of fluorescent human metaphase chromosome spreads. Chromosomes are stained with the bisbenzimidazole dye Hoechst 33342 and chromomycin A3, a dye pair used frequently in bivariate flow analysis and sorting of metaphase ...