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Vi, Agol

doi:10.1023/a:1010531228348

Cited by 10 publications

(3 citation statements)

References 170 publications

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“…If they are black holes, they may accrete from the interstellar medium or from a companion wind. With plausible assumptions, the X-ray radiation could be detectable with current spacebased observatories (Agol & Kamionkowski 2001).…”

Section: Discussionmentioning

confidence: 99%

Finding Black Holes with Microlensing

Agol

Kamionkowski

Koopmans

et al. 2002

The Astrophysical Journal

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The MACHO and OGLE collaborations have argued that the three longest duration bulge microlensing events are likely caused by nearby black holes, given the small velocities measured with microlensing parallax and nondetection of the lenses. However, these events may be due to lensing by more numerous lower mass stars at greater distances. We find a posteriori probabilities of 76%, 16%, and 4% that the three longest events are black holes, assuming a Salpeter initial mass function (IMF) and a 40 M cutoff for neutron star progenitors; the numbers depend strongly on the assumed mass function but favor a black hole for the longest event for most standard IMFs. The longest events (>600 days) have an a priori 26% probability of being black holes for a standard mass function. We propose a new technique for measuring the lens mass function using the mass distribution of long events measured with the Advanced Camera for Surveys on the Hubble Space Telescope, the Very Large Telescope Interferometer, the Space Interferometry Mission, or the Global Astrometric Interferometer for Astrophysics.Comment: final version with additional significant correction

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Section: Discussionmentioning

confidence: 99%

Finding Black Holes with Microlensing

Agol

Kamionkowski

Koopmans

et al. 2002

The Astrophysical Journal

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“…10 and 29 -31). Surprisingly, none of these proteins were translation initiation factors (10,(27)(28)(29)(30)(31). The functional roles of these IRES trans-acting factors (ITAFs) were generally addressed by in vitro translation assays (for references, see Refs.…”

Section: Viral Ribosome Landing Pads: How the Story Beganmentioning

confidence: 99%

“…The functional roles of these IRES trans-acting factors (ITAFs) were generally addressed by in vitro translation assays (for references, see Refs. [27][28][29][30][31][32]. However, recent studies provided evidence for their important functional role in vivo as well (for references, see Ref.…”

Section: Viral Ribosome Landing Pads: How the Story Beganmentioning

confidence: 99%

Internal Ribosome Entry Sites in Cellular mRNAs: Mystery of Their Existence

Komar¹,

Hatzoglou

2005

Journal of Biological Chemistry

254

256

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Although studies on viral gene expression were essential for the discovery of internal ribosome entry sites (IRESs), it is becoming increasingly clear that IRES activities are present in a significant number of cellular mRNAs. Remarkably, many of these IRES elements initiate translation of mRNAs encoding proteins that protect cells from stress (when the translation of the vast majority of cellular mRNAs is significantly impaired). The purpose of this review is to summarize the progress on the discovery and function of cellular IRESs. Recent findings on the structures of these IRESs and specifically regulation of their activity during nutritional stress, differentiation, and mitosis will be discussed.Initiation of protein synthesis in eukaryotes is a complex process requiring numerous accessory proteins called initiation factors (also termed canonical initiation factors) (1). Assembly of the 80 S ribosome at a start codon within the majority of eukaryotic mRNAs involves binding of the mRNA 5Ј-m 7 G cap structure to a group of proteins referred to as the cap-binding complex or eIF4F (which consists of three proteins: eIF4E, 1 eIF4G, and eIF4A) (1-3). This is followed by recruitment of the 40 S ribosomal subunit and associated initiation factors (43 S initiation complex comprising a 40 S subunit, eIF2⅐GTP⅐Met-tRNA i , and eIF3) and movement of the 43 S initiation complex along the 5Ј-untranslated region (5Ј-UTR) in search of the initiation codon (1-3) (Fig. 1, left panel). This mechanism of translation initiation is known as "ribosome scanning" (1-3). Initiation factor eIF4G functions as a scaffolding protein. It binds eIF4E (a capbinding protein) and eIF4A (an ATP-dependent RNA helicase, which is thought to unwind the secondary structure in the mRNA 5Ј-UTR) and bridges the mRNA and the ribosome via its interaction with the 40 S bound initiation factor eIF3 (1-3). eIF3 is a multiprotein complex directly associated with the small ribosomal subunit and was shown to impede the association of the 40 S and 60 S ribosomal subunits in the absence of eIF2⅐GTP⅐Met-tRNA i ternary complex (1-3). eIF2 binds GTP and Met-tRNA i and transfers Met-tRNA i to the 40 S ribosomal subunit (1-4). It should be noted that the availability of eIF4E for binding to eIF4G is regulated in eukaryotic cells by the phosphorylation of a small family of eIF4E-binding proteins (the 4E-BPs). Furthermore, proteins that bind the poly(A) tails of the mRNA (PABPs) were shown to facilitate initiation and recycling of ribosomes through interaction with eIF4G (1-3). However, it has become clear that some viral and eukaryotic cellular mRNAs can be translated via internal initiation, a process that involves direct binding of the ribosome to specific mRNA regions termed internal ribosome entry sites (IRESs). This translation initiation mechanism is generally independent of recognition of the 5Ј-mRNA end and involves direct recruitment of the 40 S ribosomes to the vicinity of the initiation codon (5-10) (Fig. 1, right panel). Although the debate continues over ...

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Diverse Mechanisms of RNA Recombination

Gmyl

Agol

2005

Mol Biol

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Recombination is widespread among RNA viruses, but many molecular mechanisms of this phenomenon are still poorly understood. It was believed until recently that the only possible mechanism of RNA recombination is replicative template switching, with synthesis of a complementary strand starting on one viral RNA molecule and being completed on another. The newly synthesized RNA is a primary recombinant molecule in this case. Recent studies have revealed other mechanisms of replicative RNA recombination. In addition, recombination between the genomes of RNA viruses can be nonreplicative, resulting from a joining of preexisting parental molecules. Recombination is a potent tool providing for both the variation and conservation of the genome in RNA viruses. Replicative and nonreplicative mechanisms may contribute differently to each of these evolutionary processes. In the form of trans splicing, nonreplicative recombination of cell RNAs plays an important role in at least some organisms. It is conceivable that RNA recombination continues to contribute to the evolution of DNA genomes.

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Cited by 10 publications

References 170 publications

Finding Black Holes with Microlensing

Finding Black Holes with Microlensing

Internal Ribosome Entry Sites in Cellular mRNAs: Mystery of Their Existence

Diverse Mechanisms of RNA Recombination

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