A short motif in Drosophila SECIS Binding Protein 2 provides differential binding affinity to SECIS RNA hairpins

Selenoproteins contain the amino acid selenocysteine which is encoded by a UGA Sec codon. Recoding UGA Sec requires a complex mechanism, comprising the cis-acting SECIS RNA hairpin in the 3′UTR of selenoprotein mRNAs, and trans-acting factors. Among these, the SECIS Binding Protein 2 (SBP2) is central to the mechanism. SBP2 has been so far functionally characterized only in rats and humans. In this work, we report the characterization of the Drosophila melanogaster SBP2 (dSBP2). Despite its shorter length, it retained the same selenoprotein synthesis-promoting capabilities as the mammalian counterpart. However, a major difference resides in the SECIS recognition pattern: while human SBP2 (hSBP2) binds the distinct form 1 and 2 SECIS RNAs with similar affinities, dSBP2 exhibits high affinity toward form 2 only. In addition, we report the identification of a K (lysine)-rich domain in all SBP2s, essential for SECIS and 60S ribosomal subunit binding, differing from the well-characterized L7Ae RNA-binding domain. Swapping only five amino acids between dSBP2 and hSBP2 in the K-rich domain conferred reversed SECIS-binding properties to the proteins, thus unveiling an important sequence for form 1 binding.

Three theories of liberalism for the three theories of federalism. A Hegelian turn

This paper links different political liberal theories, considered from the perspective of their moral ontology, with federal democracies. After giving a brief description of these theories, I discuss their relationship with the theoretical and institutional models of federalism. As methodological tools, the paper introduces some Hegel’s political concepts and deals with their potential application to the analysis of federalism, taken into account the case of minorities in multinational democracies. I postulate the need for a moral and institutional refinement of liberal-democratic patterns that is better able to accommodate national pluralism than has so far been achieved by traditional constitutionalism.

Statistics of transverse mode turn-on dynamics in VCSEL's

The turn-on process of a multimode VCSEL is investigated from a statistical point of view. Special attention is paid to quantities such as time jitter and bit error rate. The single-mode performance of VCSEL¿s during current modulation is compared to that of edge-emitting lasers.

Turn-on-time statistics of modulated lasers subjected to resonant weak optical feedback

We present analytical calculations of the turn-on-time probability distribution of intensity-modulated lasers under resonant weak optical feedback. Under resonant conditions, the external cavity round-trip time is taken to be equal to the modulation period. The probability distribution of the solitary laser results are modified to give reduced values of the mean turn-on-time and its variance. Numerical simulations have been carried out showing good agreement with the analytical results.

Construcción de discursos y prácticas racistas a propósito de un asentamiento rom en la ciudad de Turín, Italia

La pregunta que subyace al presente trabajo es sobre las “condiciones de posibilidad” de un campo rom, es decir, las condiciones que permiten la existencia de formas de segregación institucionalizadas, llevadas a cabo por la propia Administración Pública, en una ciudad democrática moderna; los mecanismos y dispositivos sociales que alivian – y por lo tanto permiten – la contradicción entre el discurso oficial igualitario y las prácticas oficiosas de segregación, discriminación, estigmatización de un colectivo de gitanos (rom) originarios de los países de la ex-Yugoslavia pero residentes en Italia desde hace más de una generación. La respuesta a la cuestiónconlleva la necesidad de observaciones y análisis que implican diferentes actores e instituciones, más allá del ámbito reducido del campo rom: en los espacios públicos de la ciudad, en el campo simbólico y mediático, en el campo del asociacionismo y del trabajo social y en el campo político local, nacional e internacional. Aquí como en otros ámbitos, lo marginal, lo estigmatizado nos informa de los marcos normativos propios de la “normalidad”, así que un análisis de las relaciones entre los rom del campo y sociedad mayoritaria puede proporcionar informaciones útiles tanto para comprender la cultura (o las culturas) rom como para entender mejor los mecanismos de funcionamiento de “la tribu de los payos”.

The glucose transporter 4 FQQI motif is necessary for Akt Substrate of 160-Kilodalton-dependent plasma membrane translocation but not Golgi-localized g-ear-containing Arf-binding protein-dependent entry into the insulin-responsive storage compartment.

Newly synthesized glucose transporter 4 (GLUT4) enters into the insulin-responsive storage compartment in a process that is Golgi-localized γ-ear-containing Arf-binding protein (GGA) dependent, whereas insulin-stimulated translocation is regulated by Akt substrate of 160 kDa (AS160). In the present study, using a variety of GLUT4/GLUT1 chimeras, we have analyzed the specific motifs of GLUT4 that are important for GGA and AS160 regulation of GLUT4 trafficking. Substitution of the amino terminus and the large intracellular loop of GLUT4 into GLUT1 (chimera 1-441) fully recapitulated the basal state retention, insulin-stimulated translocation, and GGA and AS160 sensitivity of wild-type GLUT4 (GLUT4-WT). GLUT4 point mutation (GLUT4-F5A) resulted in loss of GLUT4 intracellular retention in the basal state when coexpressed with both wild-type GGA and AS160. Nevertheless, similar to GLUT4-WT, the insulin-stimulated plasma membrane localization of GLUT4-F5A was significantly inhibited by coexpression of dominant-interfering GGA. In addition, coexpression with a dominant-interfering AS160 (AS160-4P) abolished insulin-stimulated GLUT4-WT but not GLUT4-F5A translocation. GLUT4 endocytosis and intracellular sequestration also required both the amino terminus and large cytoplasmic loop of GLUT4. Furthermore, both the FQQI and the SLL motifs participate in the initial endocytosis from the plasma membrane; however, once internalized, unlike the FQQI motif, the SLL motif is not responsible for intracellular recycling of GLUT4 back to the specialized compartment. Together, we have demonstrated that the FQQI motif within the amino terminus of GLUT4 is essential for GLUT4 endocytosis and AS160-dependent intracellular retention but not for the GGA-dependent sorting of GLUT4 into the insulin-responsive storage compartment.

Carnatic music: Svara, Gamaka, Motif and Raga identity

Over the last century in Karnatik music, the method ofunderstanding raga has been to break it down into its variouscomponents, svara, scale, gamaka, and phrases. In this paper, an attempt is made to define the abstract concept of raga in its entirety within the aesthetics of Karnatik music considering the various components and their symbiotic relationship. This paper also attempts to prove that theidentity of a raga exists as a whole. Section 2 explains theconcept of a fundamental musical note or svara. Section 3 illustrates the concept of gamaka or inflections. Section 4 delves into the concept of raga in detail and then flows into Section 5 which enunciates the identity of a raga in terms of svara, gamaka, and phraseology. The paper concludes in Section 6, and Section 7 gives the references.

A minimal i-motif stabilized by minor groove G:T:G:T tetrads

The repetitive DNA sequences found at telomeres and centromeres play a crucial role in the structure and function of eukaryotic chromosomes. This role may be related to the tendency observed in many repetitive DNAs to adopt non-canonical structures. Although there is an increasing recognition of the importance of DNA quadruplexes in chromosome biology, the co-existence of different quadruplex-forming elements in the same DNA structure is still a matter of debate. Here we report the structural study of the oligonucleotide d(TCGTTTCGT) and its cyclic analog d. Both sequences form dimeric quadruplex structures consisting of a minimal i-motif capped, at both ends, by a slipped minor groove-aligned G:T:G:T tetrad. These mini i-motifs, which do not exhibit the characteristic CD spectra of other i-motif structures, can be observed at neutral pH, although they are more stable under acidic conditions. This finding is particularly relevant since these oligonucleotide sequences do not contain contiguous cytosines. Importantly, these structures resemble the loop moiety adopted by an 11-nucleotide fragment of the conserved centromeric protein B (CENP-B) box motif, which is the binding site for the CENP-B.

A minimal i-motif stabilized by minor groove G:T:G:T tetrads

The repetitive DNA sequences found at telomeres and centromeres play a crucial role in the structure and function of eukaryotic chromosomes. This role may be related to the tendency observed in many repetitive DNAs to adopt non-canonical structures. Although there is an increasing recognition of the importance of DNA quadruplexes in chromosome biology, the co-existence of different quadruplex-forming elements in the same DNA structure is still a matter of debate. Here we report the structural study of the oligonucleotide d(TCGTTTCGT) and its cyclic analog d. Both sequences form dimeric quadruplex structures consisting of a minimal i-motif capped, at both ends, by a slipped minor groove-aligned G:T:G:T tetrad. These mini i-motifs, which do not exhibit the characteristic CD spectra of other i-motif structures, can be observed at neutral pH, although they are more stable under acidic conditions. This finding is particularly relevant since these oligonucleotide sequences do not contain contiguous cytosines. Importantly, these structures resemble the loop moiety adopted by an 11-nucleotide fragment of the conserved centromeric protein B (CENP-B) box motif, which is the binding site for the CENP-B.

Coregulator Control of Androgen Receptor Action by a Novel Nuclear Receptor-Binding Motif

The androgen receptor (AR) is a ligand-activated transcription factor that is essential for prostate cancer development. It is activated by androgens through its ligand-binding domain (LBD), which consists predominantly of 11 α-helices. Upon ligand binding, the last helix is reorganized to an agonist conformation termed activator function-2 (AF-2) for coactivator binding. Several coactivators bind to the AF-2 pocket through conserved LXXLL or FXXLF sequences to enhance the activity of the receptor. Recently, a small compound-binding surface adjacent to AF-2 has been identified as an allosteric modulator of the AF-2 activity and is termed binding function-3 (BF-3). However, the role of BF-3 in vivo is currently unknown, and little is understood about what proteins can bind to it. Here we demonstrate that a duplicated GARRPR motif at the N terminus of the cochaperone Bag-1L functions through the BF-3 pocket. These findings are supported by the fact that a selective BF-3 inhibitor or mutations within the BF-3 pocket abolish the interaction between the GARRPR motif(s) and the BF-3. Conversely, amino acid exchanges in the two GARRPR motifs of Bag-1L can impair the interaction between Bag-1L and AR without altering the ability of Bag-1L to bind to chromatin. Furthermore, the mutant Bag-1L increases androgen-dependent activation of a subset of AR targets in a genome-wide transcriptome analysis, demonstrating a repressive function of the GARRPR/BF-3 interaction. We have therefore identified GARRPR as a novel BF-3 regulatory sequence important for fine-tuning the activity of the AR.

The Arcuated Lintel and the "Serlian Motif". Imperial Identity, Architectural and Symbolic Interactions in Ancient Rome

Essay on the origin, use and development of the arcuated lintel in ancient Rome and the configuration of the so– called ‘Serlian motif’. These architectural elements will be related to the architecture of prestige on its technical, functional, visual and symbolic sphere. Its depictions, in addition to buildings, can offer a rich repertory of images that speak about the relations between visual culture, religion and power. Furthermore, the analyzed motifs will become important elements of the Western cultural legacy for centuries. The analysis of these events will contribute to the comprehension of the role played by some resources of ancient Rome architecture of prestige and its success

The Dialogic Turn in Educational Psychology

The increasing presence of and claim for dialogue in today"s society has already had an impact on the theory and practice of learning. Whereas in the past individual and cognitive elements were seen as crucial to learning, since about two decades ago, scientific literature indicates that culture, interaction and dialogue are the key factors. In addition, the research project of highest scientific rank and with most resources dedicated to the study of school education in the Framework Program of the European Union: INCLUD-ED shows that the practices of successful schools around Europe are in line with the dialogic approach to learning. This article presents the dialogic turn in educational psychology, consisting of moving from symbolic conceptions of mind and internalist perspectives that focus on mental schemata of previous knowledge, to theories that see intersubjectivity and communication as the primary factors in learning. The paper deepens on the second approach.