Corresponding author A.Okuda and A.Fukushima contributed equally to this workWe have obtained a novel transcriptional cofactor, termed undifferentiated embryonic cell transcription factor 1 (UTF1), from F9 embryonic carcinoma (EC) cells. This protein is expressed in EC and embryonic stem cells, as well as in germ line tissues, but could not be detected in any of the other adult mouse tissues tested. Furthermore, when EC cells are induced to differentiate, UTF1 expression is rapidly extinguished. In normal mouse embryos, UTF1 mRNA is present in the inner cell mass, the primitive ectoderm and the extra-embryonic tissues. During the primitive streak stage, the induction of mesodermal cells is accompanied by the down-regulation of UTF1 in the primitive ectoderm. However, its expression is maintained for up to 13.5 days post-coitum in the extra-embryonic tissue. Functionally, UTF1 boosts the level of transcription of the adenovirus E2A promoter. However, unlike the pluripotent cell-specific E1A-like activity, which requires the E2F sites of the E2A promoter for increased transcriptional activation, UTF1-mediated activation is dependent on the upstream ATF site of this promoter. This result indicates that UTF1 is not a major component of the E1A-like activity present in pluripotent embryonic cells. Further analyses revealed that UTF1 interacts not only with the activation domain of ATF-2, but also with the TFIID complex in vivo. Thus, UTF1 displays many of the hallmark characteristics expected for a tissue-specific transcriptional coactivator that works in early embryogenesis.

In yeast cells, independent depletion of TAFs (130, 67, 40, and 19) found specifically in TFIID results in selective effects on transcription, including a common effect on his3 core promoter function. In contrast, depletion of TAF17, which is also present in the SAGA histone acetylase complex, causes a decrease in transcription of most genes. However, TAF17-depleted cells maintain Ace1-dependent activation, and they induce de novo activation by heat shock factor in a manner predominantly associated with the activator, not the core promoter. Thus, TAF17 is broadly, but not universally, required for transcription in yeast, TAF17 depletion and TAF130 depletion each disrupt TFIID integrity yet cause different transcriptional consequences, suggesting that the widespread influence of TAF17 might not be due solely to its function in TFIID.

IB kinase (IKK) ␤ is essential for inflammatory cytokine-induced activation of nuclear factor B (NF-B). NF-B plays a pivotal role in the function of major cell types that contribute to the pathophysiological process of rheumatoid arthritis (RA). Here, we report the mechanism and the effect of the IKK␤ inhibitor N- (6-chloro-7-methoxy-9H-␤-carbolin-8-yl)-2-methylnicotinamide (ML120B), a ␤-carboline derivative, on NF-B signaling and gene activation in RA-relevant cell systems. ML120B is a potent, selective, reversible, and ATP-competitive inhibitor of IKK␤ with an IC 50 of 60 nM when evaluated in an IB␣ kinase complex assay. ML120B does not inhibit other IKK isoforms or a panel of other kinases. ML120B concentrationdependently inhibits tumor necrosis factor ␣ (TNF␣)-stimulated NF-B signaling via inhibition of IB␣ phosphorylation, degradation, and NF-B translocation into the nucleus. For the first time, we have demonstrated that in human fibroblast-like synoviocytes, TNF␣-or interleukin (IL)-1␤-induced monocyte chemoattractant protein-1 regulated on activation, normal T cell expressed and secreted and production is IKK␤-dependent. In addition, for the first time, we have demonstrated that lipopolysaccharide-or peptidoglycan-induced cytokine production in human cord blood-derived mast cells is IKK␤-dependent. In addition, in human chondrocytes, ML120B inhibited IL-1␤-induced matrix metalloproteinase production with an IC 50 of approximately 1 M. ML120B also blocked IL-1␤-induced prostaglandin E 2 production. In summary, ML120B blocked numerous NF-B-regulated cell responses that are involved in inflammation and destructive processes in the RA joint. Our findings support the evaluation of IKK␤ inhibitors as anti-inflammatory agents for the treatment of RA.

Eukaryotic transcriptional activators bind to enhancer elements and stimulate the RNA polymerase II (pol II) machinery via functionally autonomous activation domains. In yeast cells, the normal requirement for an activation domain can be bypassed by artificially connecting an enhancer-bound protein to a component of the pol II machinery. This observation suggests, but does not necessarily indicate, that the physiological role of activation domains is to recruit the pol II apparatus to promoters. Here, we show that transcriptional stimulation does not occur when the activation domain is physically disconnected from the enhancer-bound protein and transferred to components of the pol II machinery. The observation that autonomous activation domains are functional when connected to enhancer-bound proteins but not to components of the pol II machinery strongly argues that recruitment is the predominant mechanism for transcriptional activation in yeast.