STIM1 triggers a gating rearrangement at the extracellular mouth of the ORAI1 channel.

The ER-resident regulatory protein STIM1 triggers store-operated Ca(2+) entry by direct interaction with the plasma membrane Ca(2+) channel ORAI1. The mechanism of channel gating remains undefined. Here we establish that STIM1 gates the purified recombinant ORAI1 channel in vitro, and use Tb(3+) luminescence and, separately, disulfide crosslinking to probe movements of the pore-lining helices.

Vitamin C induces Tet-dependent DNA demethylation and a blastocyst-like state in ES cells.

DNA methylation is a heritable epigenetic modification involved in gene silencing, imprinting, and the suppression of retrotransposons. Global DNA demethylation occurs in the early embryo and the germ line, and may be mediated by Tet (ten eleven translocation) enzymes, which convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). Tet enzymes have been studied extensively in mouse embryonic stem (ES) cells, which are generally cultured in the absence of vitamin C, a potential cofactor for Fe(II) 2-oxoglutarate dioxygenase enzymes such as Tet enzymes.

Genome-wide mapping of 5-hydroxymethylcytosine in embryonic stem cells.

5-hydroxymethylcytosine (5hmC) is a modified base present at low levels in diverse cell types in mammals. 5hmC is generated by the TET family of Fe(II) and 2-oxoglutarate-dependent enzymes through oxidation of 5-methylcytosine (5mC). 5hmC and TET proteins have been implicated in stem cell biology and cancer, but information on the genome-wide distribution of 5hmC is limited.

Yeast H2A.Z, FACT complex and RSC regulate transcription of tRNA gene through differential dynamics of flanking nucleosomes.

FACT complex is involved in elongation and ensures fidelity in the initiation step of transcription by RNA polymerase (pol) II. Histone variant H2A.Z is found in nucleosomes at the 5'-end of many genes.