A Barcode Screen for Epigenetic Regulators Reveals a Role for the NuB4/HAT-B Histone Acetyltransferase Complex in Histone Turnover

Dynamic modification of histone proteins plays a key role in regulating gene expression. However, histones themselves can also be dynamic, which potentially affects the stability of histone modifications. To determine the molecular mechanisms of histone turnover, we developed a parallel screening method for epigenetic regulators by analyzing chromatin states on DNA barcodes. Histone turnover was quantified by employing a genetic pulse-chase technique called RITE, which was combined with chromatin immunoprecipitation and high-throughput sequencing. In this screen, the NuB4/HAT-B complex, containing the conserved type B histone acetyltransferase Hat1, was found to promote histone turnover. Unexpectedly, the three members of this complex could be functionally separated from each other as well as from the known interacting factor and histone chaperone Asf1. Thus, systematic and direct interrogation of chromatin structure on DNA barcodes can lead to the discovery of genes and pathways involved in chromatin modification and dynamics

Aborigènes: les rêveuses du désert [Australie]

[Extract] De nombreux mythes australiens evoquent des femmes creatrices de traits naturels et culturels, aux cotes d' autres etres masculins ou androgynes, hybrides d'animaux, de plantes ou de phenomenes comme Ie feu ou la pluie. Les femmes et les hommes du desert celebrent dans des ceremonies, dont l'autre sexe est exclu, la creativite de ces heros ancestraux qui ont cree Ie pays age et les lois sociales. Selon la tradition de la plupart des peuples du desert et du nord-ouest du continent, tout enfant avant de naitre s'annonce en reve a sa mere, son pere ou un autre proche. C'est par Ie reve aussi que les femmes comme les hommes peuvent recevoir la revelation de nouveaux chants rituels, de peintures Ii realiser sur Ie corps et de choregraphies a danser qui transposent dans la vie rituelle des episodes de la geste des ancetres mythiques ou des evenements historiques