scholarly journals Inhibitory Effect of Glycyrrhizin on the Phosphorylation and DNA-Binding Abilities of High Mobility Group Proteins 1 and 2 in Vitro.

2001 ◽  
Vol 24 (8) ◽  
pp. 906-911 ◽  
Author(s):  
Ryoko SAKAMOTO ◽  
Maiko OKANO ◽  
Hiroko TAKENA ◽  
Kenzo OHTSUKI
1988 ◽  
Vol 8 (8) ◽  
pp. 3406-3414
Author(s):  
H F Yang-Yen ◽  
L I Rothblum

A 16,000-dalton, high-mobility-group-like (HMG-like) DNA-binding protein, referred to as p16, has been purified to homogeneity from Novikoff hepatoma ascites cells. p16 binds specifically to a portion of the 5' flanking region of the rat rRNA gene (-620 to -417), which is part of the upstream activator sequence identified previously (B. G. Cassidy, H.-F. Yang-Yen, and L. I. Rothblum, Mol. Cell. Biol. 6:2766-2773, 1986). p16 also binds to a segment of the external transcribed spacer (+352 to +545). In vitro reconstituted transcription experiments demonstrated that the addition of p16 stimulated rRNA synthesis up to ca. fourfold. The stimulation was dose dependent and saturable. The effect of p16 on ribosomal gene transcription was also dependent on the presence of either the upstream or the downstream DNA-binding site, or both. The amino acid composition of p16 is very similar to that of HMG-I, suggesting that p16 may be a member of the HMG-I family of proteins. In this case, our results suggest that HMG proteins may play an important role in the regulation of the rRNA gene expression.


1988 ◽  
Vol 8 (8) ◽  
pp. 3406-3414 ◽  
Author(s):  
H F Yang-Yen ◽  
L I Rothblum

A 16,000-dalton, high-mobility-group-like (HMG-like) DNA-binding protein, referred to as p16, has been purified to homogeneity from Novikoff hepatoma ascites cells. p16 binds specifically to a portion of the 5' flanking region of the rat rRNA gene (-620 to -417), which is part of the upstream activator sequence identified previously (B. G. Cassidy, H.-F. Yang-Yen, and L. I. Rothblum, Mol. Cell. Biol. 6:2766-2773, 1986). p16 also binds to a segment of the external transcribed spacer (+352 to +545). In vitro reconstituted transcription experiments demonstrated that the addition of p16 stimulated rRNA synthesis up to ca. fourfold. The stimulation was dose dependent and saturable. The effect of p16 on ribosomal gene transcription was also dependent on the presence of either the upstream or the downstream DNA-binding site, or both. The amino acid composition of p16 is very similar to that of HMG-I, suggesting that p16 may be a member of the HMG-I family of proteins. In this case, our results suggest that HMG proteins may play an important role in the regulation of the rRNA gene expression.


2001 ◽  
Vol 21 (9) ◽  
pp. 3096-3104 ◽  
Author(s):  
Sébastien Lopez ◽  
Magda Livingstone-Zatchej ◽  
Sabine Jourdain ◽  
Fritz Thoma ◽  
André Sentenac ◽  
...  

ABSTRACT Transcription of yeast class III genes involves the formation of a transcription initiation complex that comprises RNA polymerase III (Pol III) and the general transcription factors TFIIIB and TFIIIC. Using a genetic screen for positive regulators able to compensate for a deficiency in a promoter element of the SNR6 gene, we isolated the NHP6A and NHP6B genes. Here we show that the high-mobility-group proteins NHP6A and NHP6B are required for the efficient transcription of the SNR6 gene both in vivo and in vitro. The transcripts of wild-type and promoter-defectiveSNR6 genes decreased or became undetectable in annhp6AΔ nhp6BΔ double-mutant strain, and the protection over the TATA box of the wild-type SNR6 gene was lost innhp6AΔ nhp6BΔ cells at 37°C. In vitro, NHP6B specifically stimulated the transcription of SNR6 templates up to fivefold in transcription assays using either cell nuclear extracts from nhp6AΔ nhp6BΔ cells or reconstituted transcription systems. Finally, NHP6B activated SNR6transcription in a TFIIIC-independent assay. These results indicate that besides the general transcription factors TFIIIB and TFIIIC, additional auxilliary factors are required for the optimal transcription of at least some specific Pol III genes.


2012 ◽  
Vol 195 (2) ◽  
pp. 378-388 ◽  
Author(s):  
Francisco García-Heras ◽  
Javier Abellón-Ruiz ◽  
Francisco J. Murillo ◽  
S. Padmanabhan ◽  
Montserrat Elías-Arnanz

ABSTRACTThe CarD-CarG complex controls various cellular processes in the bacteriumMyxococcus xanthusincluding fruiting body development and light-induced carotenogenesis. The CarD N-terminal domain, which defines the large CarD_CdnL_TRCF protein family, binds to CarG, a zinc-associated protein that does not bind DNA. The CarD C-terminal domain resembles eukaryotic high-mobility-group A (HMGA) proteins, and its DNA binding AT hooks specifically recognize the minor groove of appropriately spaced AT-rich tracts. Here, we investigate the determinants of the only known CarD binding site, the one crucial in CarD-CarG regulation of the promoter of thecarQRSoperon (PQRS), a light-inducible promoter dependent on the extracytoplasmic function (ECF) σ factor CarQ.In vitro, mutating either of the 3-bp AT tracts of this CarD recognition site (TTTCCAGAGCTTT) impaired DNA binding, shifting the AT tracts relative to PQRShad no effect or marginally lowered DNA binding, and replacing the native site by the HMGA1a binding one at the human beta interferon promoter (with longer AT tracts) markedly enhanced DNA binding.In vivo, however, all of these changes deterred PQRSactivation in wild-typeM. xanthus, as well as in a strain with the CarD-CarG pair replaced by theAnaeromyxobacter dehalogenansCarD-CarG (CarDAd-CarGAd). CarDAd-CarGAdis functionally equivalent to CarD-CarG despite the lower DNA binding affinityin vitroof CarDAd, whose C-terminal domain resembles histone H1 rather than HMGA. We show that CarD physically associates with RNA polymerase (RNAP) specifically via interactions with the RNAP β subunit. Our findings suggest that CarD regulates a light-inducible, ECF σ-dependent promoter by coupling RNAP recruitment and binding to a specific DNA site optimized for affinity and position.


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