During Arabidopsis embryogenesis, a single cell is specified to become the founder cell of the root meristem — the hypophysis — in response to signals from adjacent cells. Hypophysis specification requires an auxin-responsive transcription factor, MONOPTEROS (MP), which promotes transport of auxin from the embryo to the hypophysis precursor. Here, MP target genes are identified and the means by which they mediate root formation is shown

To study the changes in chromatin structure that accompany zygotic genome activation and pluripotency during the maternal–zygotic transition (MZT), the genomic locations of histone H3 modifications and RNA polymerase II have been mapped during this transition in zebrafish embryos. H3 lysine 27 trimethylation and H3 lysine 4 trimethylation are only detected after MZT; evidence is provided that the bivalent chromatin domains found in cultured embryonic stem cells also exist in embryos

Quantification of the interaction of T-cell receptors with their peptide–MHC ligands in two–dimensional membranes is shown to yield larger dissociation rate constants than previous assays where one of the interacting partners was in solution