Genetic databases.

A simple visit to the doctor in a few years' time might see you taking part in the largest research project ever conducted in the UK. The ethical and logistical challenges of this study are as complex as the scientific ones.'

Repression of CDK1 and other genes with CDE and CHR promoter elements during DNA damage-induced G(2)/M arrest in human cells.

Entry into mitosis is controlled by the cyclin-dependent kinase CDK1 and can be delayed in response to DNA damage. In some systems, such G(2)/M arrest has been shown to reflect the stabilization of inhibitory phosphorylation sites on CDK1. In human cells, full G(2) arrest appears to involve additional mechanisms.

Construction by gene targeting in human cells of a "conditional' CDC2 mutant that rereplicates its DNA.

We describe a novel gene targeting strategy for the genetic analysis of essential genes in mammalian cells and its use to study the role of the cell cycle control gene CDC2 in human cells. A cell line (HT2-19) was generated in which endogenous CDC2 gene expression and cell viability depend on the presence of an inducer in the growth medium. In the absence of inducer, HT2-19 cells undergo extensive DNA rereplication and apoptosis.