Ribonucleoproteins

Publication Title: 
Open Biology

Multi-cellular organisms need to successfully link cell growth and metabolism to environmental cues during development. Insulin receptor-target of rapamycin (InR-TOR) signalling is a highly conserved pathway that mediates this link. Herein, we describe poly, an essential gene in Drosophila that mediates InR-TOR signalling. Loss of poly results in lethality at the third instar larval stage, but only after a stage of extreme larval longevity.

Author(s): 
Bolukbasi, Ekin
Vass, Sharron
Cobbe, Neville
Nelson, Bryce
Simossis, Victor
Dunbar, Donald R.
Heck, Margarete M. S.
Publication Title: 
PloS One

Nutrient-deprivation autophagy factor-1 (NAF-1) (synonyms: Cisd2, Eris, Miner1, and Noxp70) is a [2Fe-2S] cluster protein immune-detected both in endoplasmic reticulum (ER) and mitochondrial outer membrane. It was implicated in human pathology (Wolfram Syndrome 2) and in BCL-2 mediated antagonization of Beclin 1-dependent autophagy and depression of ER calcium stores. To gain insights about NAF-1 functions, we investigated the biochemical properties of its 2Fe-2S cluster and sensitivity of those properties to small molecules.

Author(s): 
Tamir, Sagi
Zuris, John A.
Agranat, Lily
Lipper, Colin H.
Conlan, Andrea R.
Michaeli, Dorit
Harir, Yael
Paddock, Mark L.
Mittler, Ron
Cabantchik, Zvi Ioav
Jennings, Patricia A.
Nechushtai, Rachel
Publication Title: 
The Journal of Biological Chemistry

Human TDP-43 represents the main component of neuronal inclusions found in patients with neurodegenerative diseases, especially frontotemporal lobar degeneration and amyotrophic lateral sclerosis. In vitro and in vivo studies have shown that the TAR DNA-binding protein 43 (TDP-43) Drosophila ortholog (TBPH) can biochemically and functionally overlap the properties of the human factor.

Author(s): 
Romano, Maurizio
Buratti, Emanuele
Romano, Giulia
Klima, Raffaella
Del Bel Belluz, Lisa
Stuani, Cristiana
Baralle, Francisco
Feiguin, Fabian
Publication Title: 
Cell

We have analyzed the de novo telomere synthesis catalyzed by the enzyme telomere terminal transferase (telomerase) from Tetrahymena. Oligonucleotides representing the G-rich strand of telomeric sequences from five different organisms specifically primed the addition of TTGGGG repeats in vitro, suggesting that primer recognition may involve a DNA structure unique to these oligonucleotides. The sequence at the 3' end of the oligonucleotide primer specified the first nucleotide added in the reaction.

Author(s): 
Greider, C. W.
Blackburn, E. H.
Publication Title: 
Genes & Development

The reverse transcriptase telomerase is a ribonucleoprotein complex that adds telomeric repeats to chromosome ends, using a sequence within its endogenous RNA component as a template. Although templating domains of telomerase RNA have been studied in detail, little is known about the roles of the remaining residues, particularly in yeast. We examined the functions of nontemplate telomerase residues in the telomerase RNA of budding yeast Kluyveromyces lactis.

Author(s): 
Roy, J.
Fulton, T. B.
Blackburn, E. H.
Publication Title: 
The Journal of Cell Biology

Telomeres are the protein-nucleic acid structures at the ends of eukaryote chromosomes. Tandem repeats of telomeric DNA are templated by the RNA component (TER1) of the ribonucleoprotein telomerase. These repeats are bound by telomere binding proteins, which are thought to interact with other factors to create a higher-order cap complex that stabilizes the chromosome end.

Author(s): 
Smith, C. D.
Blackburn, E. H.
Publication Title: 
Genes & Development

The ribonucleoprotein enzyme telomerase synthesizes telomeric DNA by copying a template sequence in the telomerase RNA. We studied the functional roles of specific residues in the Tetrahymena telomerase RNA template region. Unexpectedly, mutation of certain templating residues caused dramatic effects on specific aspects of the enzyme reaction, including loss of enzymatic fidelity and premature product dissociation. None of these fundamental changes in enzymatic action are explainable by altered base-pairing between the telomerase RNA and DNA substrate.

Author(s): 
Gilley, D.
Lee, M. S.
Blackburn, E. H.
Publication Title: 
Cell

The RNA moiety of the ribonucleoprotein enzyme telomerase contains the template for telomeric DNA synthesis. We present a secondary structure model for telomerase RNA, derived by a phylogenetic comparative analysis of telomerase RNAs from seven tetrahymenine ciliates. The telomerase RNA genes from Tetrahymena malaccensis, T. pyriformis, T. hyperangularis, T. pigmentosa, T. hegewishii, and Glaucoma chattoni were cloned, sequenced, and compared with the previously cloned RNA gene from T. thermophila and with each other.

Author(s): 
Romero, D. P.
Blackburn, E. H.
Publication Title: 
Nature Structural Biology

Telomerases contain an essential RNA subunit (TER), as well as an essential protein reverse transcriptase subunit (TERT). The RNA subunit includes a short template region that is copied into telomeric DNA, but otherwise it is large and divergent. However, phylogenetic studies have revealed a conserved core secondary structure for TER. Much of the divergence can be accounted for by the acquisition of different types of RNA domains that function in RNA stabilization.

Author(s): 
Blackburn, E. H.
Publication Title: 
Genome / National Research Council Canada = GÈnome / Conseil National De Recherches Canada

Telomeres stabilize chromosomal ends and allow their complete replication in vivo. In diverse eukaryotes, the essential telomeric DNA sequence consists of variable numbers of tandem repeats of simple, G + C rich sequences, with a strong strand bias of G residues on the strand oriented 5' to 3' toward the chromosomal terminus. This strand forms a protruding 3' over-hang at the chromosomal terminus in three different eukaryotes analyzed.

Author(s): 
Blackburn, E. H.
Greider, C. W.
Henderson, E.
Lee, M. S.
Shampay, J.
Shippen-Lentz, D.

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