The archaeal transcription apparatus is chimeric: its core components (RNA polymerase and basal factors) closely resemble those of eukaryotic RNA polymerase II, but the putative archaeal transcriptional regulators are overwhelmingly of bacterial type. Particular interest attaches to how these bacterial-type effectors, especially activators, regulate a eukaryote-like transcription system. The hyperthermophilic archaeon Methanocaldococcus jannaschii encodes a potent transcriptional activator, Ptr2, related to the Lrp/AsnC family of bacterial regulators. Ptr2 activates rubredoxin 2 (rb2) transcription through a bipartite upstream activating site (UAS), and conveys its stimulatory effects on its cognate transcription machinery through direct recruitment of the TATA binding protein (TBP). A functional dissection of the highly constrained architecture of the rb2 promoter shows that a 'one-site' minimal UAS suffices for activation by Ptr2, and specifies the required placement of this site. The presence of such a simplified UAS upstream of the natural rubrerythrin (rbr) promoter also suffices for positive regulation by Ptr2 in vitro, and TBP recruitment remains the primary means of transcriptional activation at this promoter.
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http://dx.doi.org/10.1111/j.1365-2958.2005.04563.x | DOI Listing |
Microbiome
November 2024
UMR5240 Microbiologie Adaptation Et Pathogénie, Université, INSA Lyon, CNRS, Claude Bernard Lyon 1, Villeurbanne, 69621, France.
Genome Res
November 2024
Stanford University, Arc Institute.
Histone proteins have traditionally been thought to be restricted to eukaryotes and most archaea, with eukaryotic nucleosomal histones deriving from their archaeal ancestors. In contrast, bacteria lack histones as a rule. However, histone proteins have recently been identified in a few bacterial clades, most notably the phylum Bdellovibrionota, and these histones have been proposed to exhibit a range of divergent features compared to histones in archaea and eukaryotes.
View Article and Find Full Text PDFVirus Evol
October 2024
State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Rd, Qingdao 266071, China.
Ostreid herpesvirus 1 (OsHV-1), a member of the family (order ), is a major pathogen of bivalves. However, the molecular details of the malacoherpesvirus infection cycle and its overall similarity to the replication of mammalian herpesviruses (family ) remain obscure. Here, to gain insights into the OsHV-1 biology, we performed long-read sequencing of infected blood clams, , which yielded over one million OsHV-1 long reads.
View Article and Find Full Text PDFStructure
October 2024
RNAP Laboratory, Institute for Structural and Molecular Biology, University College London, London WC1E 6BT, UK. Electronic address:
N-utilization substance A (NusA) is a regulatory factor with pleiotropic functions in gene expression in bacteria. Archaea encode two conserved small proteins, NusA1 and NusA2, with domains orthologous to the two RNA binding K Homology (KH) domains of NusA. Here, we report the crystal structures of NusA2 from Sulfolobus acidocaldarius and Saccharolobus solfataricus obtained at 3.
View Article and Find Full Text PDFProtein Sci
November 2024
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA.
The β and β' subunits of the RNA polymerase (RNAP) are large proteins with complex multi-domain architectures that include several insertional domains. Here, we analyze the domain organizations of RNAP-β and RNAP-β' using sequence, experimentally determined structures and AlphaFold structure predictions. We observe that lineage-specific insertional domains in bacterial RNAP-β belong to a group that we call BEAN (broadly embedded annex).
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