Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Stephen J. Royle describes a cutting-edge study that provided definitive evidence for the first time that the kinetochore fibre is a bundle of parallel microtubules.
Retinoic acid regulates transcription by interacting with nuclear retinoic acid receptors, which bind to retinoic acid response elements near target genes. Recent studies have refined our knowledge of retinoic acid function in the limb, which serves as a paradigm for understanding how it regulates other developmental processes, such as somitogenesis, neuronal differentiation and organogenesis.