In the central domain of fission yeast centromeres, the kinetochore is assembled on CENP-A(Cnp1) nucleosomes. Normally, small interfering RNAs generated from flanking outer repeat transcripts direct histone H3 lysine 9 methyltransferase Clr4 to homologous loci to form heterochromatin. Outer repeats, RNA interference (RNAi), and centromeric heterochromatin are required to establish CENP-A(Cnp1) chromatin. We demonstrated that tethering Clr4 via DNA-binding sites at euchromatic loci induces heterochromatin assembly, with or without active RNAi. This synthetic heterochromatin completely substitutes for outer repeats on plasmid-based minichromosomes, promoting de novo CENP-A(Cnp1) and kinetochore assembly, to allow their mitotic segregation, even with RNAi inactive. Thus, the role of outer repeats in centromere establishment is simply the provision of RNAi substrates to direct heterochromatin formation; H3K9 methylation-dependent heterochromatin is alone sufficient to form functional centromeres.
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http://dx.doi.org/10.1126/science.1172026 | DOI Listing |
Arch Microbiol
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Department of Stomatology, The Second Affiliated Hospital, Hengyang Medical College, University of South China, Hengyang, 421001, Hunan, China.
Treponema denticola, a bacterium that forms a "red complex" with Porphyromonas gingivalis and Tannerella forsythia, is associated with periodontitis, pulpitis, and other oral infections. The major surface protein (Msp) is a surface glycoprotein with a relatively well-established overall domain structure (N-terminal, central and C-terminal regions) and a controversial tertiary structure. As one of the key virulence factors of T.
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March 2025
School of Pharmacy and Medical Science, Griffith University, Gold Coast Campus, Queensland, 4222, Australia; Institute for Biomedicine and Glycomics, Griffith University, Gold Coast Campus, Queensland, 4222, Australia. Electronic address:
Moraxella lincolnii is a Gram-negative bacterium that resides in the upper respiratory tract (URT) of humans and may have a role as a member of a protective microbial community. Structural characterisation studies of its outer membrane glycan structures are very limited. We report here the isolation and structural characterisation (NMR, GLC-MS) of a capsular polysaccharide (CPS) and an oligosaccharide (OS) (lipooligosaccharide (LOS)-derived) isolated from strain CCUG 52988.
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MOA Key Laboratory of Animal Virology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China; Department of Veterinary Medicine, College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China. Electronic address:
Nat Cell Biol
January 2025
Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.
Outer mitochondrial membrane (OMM) proteins communicate with the cytosol and other organelles, including the endoplasmic reticulum. This communication is important in thermogenic adipocytes to increase the energy expenditure that controls body temperature and weight. However, the regulatory mechanisms of OMM protein insertion are poorly understood.
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December 2024
Laboratório de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, Brazil.
Pathogenic are spirochetes that cause leptospirosis, a worldwide zoonotic disease. Leptospirosis affects humans and animals, with approximately 1 million human infections and 60,000 deaths per year. The diversity of leptospiral strains and serovars allied to the fact that pathogenesis is not yet fully understood, make the development of an effective vaccine against leptospirosis a challenge.
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