Revised Lithostratigraphy of the Sonsela Member (Chinle Formation, Upper Triassic) in the Southern Part of Petrified Forest National Park, Arizona

BACKGROUND: Recent revisions to the Sonsela Member of the Chinle Formation in Petrified Forest National Park have presented a three-part lithostratigraphic model based on unconventional correlations of sandstone beds. As a vertebrate faunal transition is recorded within this stratigraphic interval, these correlations, and the purported existence of a depositional hiatus (the Tr-4 unconformity) at about the same level, must be carefully re-examined. METHODOLOGY/PRINCIPAL FINDINGS: Our investigations demonstrate the neglected necessity of walking out contacts and mapping when constructing lithostratigraphic models, and providing UTM coordinates and labeled photographs for all measured sections. We correct correlation errors within the Sonsela Member, demonstrate that there are multiple Flattops One sandstones, all of which are higher than the traditional Sonsela sandstone bed, that the Sonsela sandstone bed and Rainbow Forest Bed are equivalent, that the Rainbow Forest Bed is higher than the sandstones at the base of Blue Mesa and Agate Mesa, that strata formerly assigned to the Jim Camp Wash beds occur at two stratigraphic levels, and that there are multiple persistent silcrete horizons within the Sonsela Member. CONCLUSIONS/SIGNIFICANCE: We present a revised five-part model for the Sonsela Member. The units from lowest to highest are: the Camp Butte beds, Lot's Wife beds, Jasper Forest bed (the Sonsela sandstone)/Rainbow Forest Bed, Jim Camp Wash beds, and Martha's Butte beds (including the Flattops One sandstones). Although there are numerous degradational/aggradational cycles within the Chinle Formation, a single unconformable horizon within or at the base of the Sonsela Member that can be traced across the entire western United States (the "Tr-4 unconformity") probably does not exist. The shift from relatively humid and poorly-drained to arid and well-drained climatic conditions began during deposition of the Sonsela Member (low in the Jim Camp Wash beds), well after the Carnian-Norian transition

CSN controls NF-κB by deubiquitinylation of IκBα

The COP9 signalosome (CSN) is a conserved protein complex that regulates assembly and activity of cullin-RING ubiquitin ligases (CRLs). Ubiquitin-dependent degradation of the NF-κB inhibitor IκBα preceeds nuclear translocation of NF-κB. For the first time, we show here an inducible interaction of the CSN with IκBα and that the CSN controls IκBα and NF-κB activity. Strikingly, disruption of the CSN by a small interfering RNA-mediated knockdown of single CSN subunits results in a reduced re-accumulation of IκBα and prolonged nuclear translocation of NF-κB in TNFα-stimulated cells. The control of IκBα by the CSN is regulated by deubiquitinylation of IκBα conferred by the CSN-associated deubiquitinylase USP15. Protein expression levels of cullin1 and the CRL substrate adapter β-TrCP are reduced in nonstimulated cells with a disrupted function of the CSN, which might account for an impaired basal turnover of IκBα. We propose that the CSN controls both CRL activity and stability of the CRL substrate IκBα. In consequence, basal and signal-induced CRL-dependent turnover of IκBα is precisely adapted to specific cellular needs