The gammaherpesviral TATA-box-binding protein directly interacts with the CTD of host RNA Pol II to direct late gene transcription.

ß- and γ-herpesviruses include the oncogenic human viruses Kaposi's sarcoma-associated virus (KSHV) and Epstein-Barr virus (EBV), and human cytomegalovirus (HCMV), which is a significant cause of congenital disease. Near the end of their replication cycle, these viruses transcribe their late genes in a manner distinct from host transcription. Late gene transcription requires six virally encoded proteins, one of which is a functional mimic of host TATA-box-binding protein (TBP) that is also involved in recruitment of RNA polymerase II (Pol II) via unknown mechanisms. Here, we applied biochemical protein interaction studies together with electron microscopy-based imaging of a reconstituted human preinitiation complex to define the mechanism underlying Pol II recruitment. These data revealed that the herpesviral TBP, encoded by ORF24 in KSHV, makes a direct protein-protein contact with the C-terminal domain of host RNA polymerase II (Pol II), which is a unique feature that functionally distinguishes viral from cellular TBP. The interaction is mediated by the N-terminal domain (NTD) of ORF24 through a conserved motif that is shared in its ß- and γ-herpesvirus homologs. Thus, these herpesviruses employ an unprecedented strategy in eukaryotic transcription, wherein promoter recognition and polymerase recruitment are facilitated by a single transcriptional activator with functionally distinct domains.

Conserved CxnC Motifs in Kaposi's Sarcoma-Associated Herpesvirus ORF66 Are Required for Viral Late Gene Expression and Are Essential for Its Interaction with ORF34.

Late gene transcription in the beta- and gammaherpesviruses depends on a set of virally encoded transcriptional activators (vTAs) that hijack the host transcriptional machinery and direct it to a subset of viral genes that are required for completion of the viral replication cycle and capsid assembly. In Kaposi's sarcoma-associated herpesvirus (KSHV), these vTAs are encoded by ORF18, ORF24, ORF30, ORF31, ORF34, and ORF66. Assembly of the vTAs into a complex is critical for late gene transcription, and thus, deciphering the architecture of the complex is central to understanding its transcriptional regulatory activity. Here, we generated an ORF66-null virus and confirmed that it fails to produce late genes and infectious virions. We show that ORF66 is incorporated into the vTA complex primarily through its interaction with ORF34, which is dependent upon a set of four conserved cysteine-rich motifs in the C-terminal domain of ORF66. While both ORF24 and ORF66 occupy the canonical K8.1 late gene promoter, their promoter occupancy requires the presence of the other vTAs, suggesting that sequence-specific, stable binding requires assembly of the entire complex on the promoter. Additionally, we found that ORF24 expression is impaired in the absence of a stable vTA complex. This work extends our knowledge about the architecture of the KSHV viral preinitiation complex and suggests that it functions as a complex to recognize late gene promoters.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV; human herpesvirus 8) is an oncogenic gammaherpesvirus that is the causative agent of multiple human cancers. The release of infectious virions requires the production of capsid proteins and other late genes, whose production is transcriptionally controlled by a complex of six virally encoded proteins that hijack the host transcription machinery. It is poorly understood how this complex assembles or what function five of its six components play in transcription. Here, we demonstrate that ORF66 is an essential component of this complex in KSHV and that its inclusion in the complex depends upon its C-terminal domain, which contains highly conserved cysteine-rich motifs reminiscent of zinc finger motifs. Additionally, we examined the assembly of the viral preinitiation complex at late gene promoters and found that while sequence-specific binding of late gene promoters requires ORF24, it additionally requires a fully assembled viral preinitiation complex.

The Interaction between ORF18 and ORF30 Is Required for Late Gene Expression in Kaposi's Sarcoma-Associated Herpesvirus.

In the beta- and gammaherpesviruses, a specialized complex of viral transcriptional activators (vTAs) coordinate to direct expression of virus-encoded late genes, which are critical for viral assembly and whose transcription initiates only after the onset of viral DNA replication. The vTAs in Kaposi's sarcoma-associated herpesvirus (KSHV) are ORF18, ORF24, ORF30, ORF31, ORF34, and ORF66. While the general organization of the vTA complex has been mapped, the individual roles of these proteins and how they coordinate to activate late gene promoters remain largely unknown. Here, we performed a comprehensive mutational analysis of the conserved residues in ORF18, which is a highly interconnected vTA component. Surprisingly, the mutants were largely selective for disrupting the interaction with ORF30 but not the other three ORF18 binding partners. Furthermore, disrupting the ORF18-ORF30 interaction weakened the vTA complex as a whole, and an ORF18 point mutant that failed to bind ORF30 was unable to complement an ORF18 null virus. Thus, contacts between individual vTAs are critical as even small disruptions in this complex result in profound defects in KSHV late gene expression.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi's sarcoma and other B-cell cancers and remains a leading cause of death in immunocompromised individuals. A key step in the production of infectious virions is the transcription of viral late genes, which generates capsid and structural proteins and requires the coordination of six viral proteins that form a complex. The role of these proteins during transcription complex formation and the importance of protein-protein interactions are not well understood. Here, we focused on a central component of the complex, ORF18, and revealed that disruption of its interaction with even a single component of the complex (ORF30) prevents late gene expression and completion of the viral lifecycle. These findings underscore how individual interactions between the late gene transcription components are critical for both the stability and function of the complex.

Síndrome metabólico y sus complicaciones: el pie diabético / Metabolic syndrome and its complications: The diabetic foot

Resumen En la actualidad, México ocupa el primer lugar con obesidad infantil y el segundo con obesidad en el adulto. Este fenómeno ya ha alcanzado niveles de pandemia, por lo que de no evitar que continúe aumentando el número de pacientes obesos, en pocos años la cantidad de discapacitados a causa de alteraciones metabólicas será alarmante. En esta revisión se pretenden establecer las causas del síndrome metabólico, los mecanismos que se alteran para conducirá diabetes mellitus, y se mencionan los mecanismos fisiológicos que se alteran en la condición de hiperglucemia. Y dentro de las consecuencias que resultan de esta enfermedad, analizar una de las que más cuesta al paciente y a la familia como lo es el pie diabético.

Abstract Mexico currently occupies the first place with childhood obesity and the second with adult obesity. This phenomenon has already reached pandemic levels so if the increasing number of obese patients is not prevented, in a fewyears the number of patients with disabilities resulting from metabolic alterations will be alarming. This review aims to establish the causes of the metabolic syndrome, the mechanisms that are altered and lead to diabetes mellitus, also we will mention the physiological mechanisms altered in hyperglycemia and its consequences. We will analyze one of the diseases with the highest costs for the patient and their family: the diabetic foot.

Biconically tapered fiber optic probes for rapid label-free immunoassays.

We report use of U-shaped biconically tapered optical fibers (BTOF) as probes for label-free immunoassays. The tapered regions of the sensors were functionalized by immobilization of immunoglobulin-G (Ig-G) and tested for detection of anti-IgG at concentrations of 50 ng/mL to 50 µg/mL. Antibody-antigen reaction creates a biological nanolayer modifying the waveguide structure leading to a change in the sensor signal, which allows real-time monitoring. The kinetics of the antibody (mouse Ig-G)-antigen (rabbit anti-mouse IgG) reactions was studied. Hydrofluoric acid treatment makes the sensitive region thinner to enhance sensitivity, which we confirmed by experiments and simulations. The limit of detection for the sensor was estimated to be less than 50 ng/mL. Utilization of the rate of the sensor peak shift within the first few minutes of the antibody-antigen reaction is proposed as a rapid protein detection method.

Optical coherence tomography for guiding wire into a side branch coronary artery with flush total occlusion.

We report a case of flush occlusion, where a novel use of optical coherence tomography (OCT) helped in successful crossing and stenting of the lesion.

Efecto de la corrección óptica sobre la sintomatología en escolares con ametropías bajas / Effect of optical correction on school children with low ametropia

En este estudio se comparó la evolución de la sintomatología en una muestra de 60 jóvenes entre 6 y 15 años de edad con ametropias bajas sintomáticos, en Bogotá, Colombia. El estudio experimental dividió aleatoriamente la muestra en dos grupos iguales, un grupo al que se le prescribió corrección óptica de uso permanente y un grupo de control al que no se le prescribio corrección óptica. Los dos grupos presentaron una sintomatología similar inicialmente: hiperemia bulbar 60%, hiperemia tarsal 50%, ardor ocular 40%, prurito 38%, cefalea frontal 30%, lagrimeo 13%, Astenopia al leer 21%, entre otros. Después del uso permanente de la corrección óptica por tres meses el grupo uno, presento una disminución considerable de la sintomatología, de doce síntomas iniciales, desaparecieron siete de ellos y los cinco restantes presentaron una disminución entre el 86% y el 59%. Este resultado nos indica que el uso de la corrección óptica en niños con ametropias bajas, elimina o disminuye drásticamente la sintomatología de los niños independientemente de su amplitud de acomodación.