Fragments of the HIV-1 Tat protein specifically bind TAR RNA

Proteolytically produced carboxyl-terminal fragments of the human immunodeficiency virus type-1 (HIV-1) Tat protein that include a conserved region rich in arginine and lysine bind specifically to transactivation response RNA sequences (TAR). A chemically synthesized 14-residue peptide spanning the basic subdomain also recognizes TAR, identifying this subdomain as central for RNA interaction. TAR RNA forms a stable hairpin that includes a six-residue loop, a trinucleotide pyrimidine bulge, and extensive duplex structure. Competition and interference experiments show that the Tat-derived fragments bind to double-stranded RNA and interact specifically at the pyrimidine bulge and adjacent duplex of TAR.     

Biologic features of HIV-1 that correlate with virulence in the host

Individuals infected with the human immunodeficiency virus type 1 (HIV-1) may be asymptomatic or have AIDS-related complex or the acquired immuno deficiency syndrome (AIDS). Little is known about the factors that influence progression of infection to AIDS. In this study of isolates of HIV-1 obtained at intervals during the infection of four individuals, the development of disease was found to be correlated with the emergence of HIV-1 variants that were more cytopathic in vitro as the disease progressed and that replicated more efficiently in a wide variety of different human cells. The biologic properties of HIV-1 in vitro thus appear to reflect its virulence in the host. Further studies of such sequentially isolated viruses may lead to the identification of viral genes that govern pathogenesis.     

Characterization of a human TAR RNA-binding protein that activates the HIV-1 LTR

Human immunodeficiency virus type 1 (HIV-1) gene expression is activated by Tat, a virally encoded protein. Tat trans-activation requires viral (trans-activation--responsive; TAR) RNA sequences located in the R region of the long terminal repeat (LTR). Existing evidence suggests that Tat probably cooperates with cellular factors that bind to TAR RNA in the overall trans-activation process. A HeLa complementary DNA was isolated and characterized that encodes a TAR RNA-binding protein (TRBP). TRBP activated the HIV-1 LTR and was synergistic with Tat function.     

Unexpectedly high levels of HIV-1 RNA and protein synthesis in a cytocidal infection

The expression of a laboratory strain of HIV-1 (HTLV-IIIB) has been studied in mitogen-stimulated peripheral blood lymphocytes (PBLs) and in two lymphoid cell lines (CEM cells and C8166 cells). HIV-expressing cells contained from 300,000 to 2,500,000 copies of viral RNA per cell. Near-synchronous expression of an active infection could be achieved in C8166 cells. In these cells, the high copy numbers of viral RNA used as much as 40% of total protein synthesis for the production of viral gag protein, with high levels of viral RNA and protein synthesis preceding cell death by 2 to 4 days.     

OsDXR interacts with OsMORF1 to regulate chloroplast development and the RNA editing of chloroplast genes in rice

Plant chlorophyll biosynthesis and chloroplast development are two complex processes that are regulated by exogenous and endogenous factors. In this study, we identified OsDXR, a gene encoding a reductoisomerase that positively regulates chlorophyll biosynthesis and chloroplast development in rice. OsDXR knock-out lines displayed the albino phenotype and could not complete the whole life cycle process. OsDXR was highly expressed in rice leaves, and subcellular localization indicated that OsDXR i...     

Inhibitors of strand transfer that prevent integration and inhibit HIV-1 replication in cells

Integrase is essential for human immunodeficiency virus-type 1 (HIV-1) replication; however, potent inhibition of the isolated enzyme in biochemical assays has not readily translated into antiviral activity in a manner consistent with inhibition of integration. In this report, we describe diketo acid inhibitors of HIV-1 integrase that manifest antiviral activity as a consequence of their effect on integration. The antiviral activity of these compounds is due exclusively to inhibition of one of the two catalytic functions of integrase, strand transfer.     

Focused evolution of HIV-1 neutralizing antibodies revealed by structures and deep sequencing

Antibody VRC01 is a human immunoglobulin that neutralizes about 90% of HIV-1 isolates. To understand how such broadly neutralizing antibodies develop, we used x-ray crystallography and 454 pyrosequencing to characterize additional VRC01-like antibodies from HIV-1-infected individuals. Crystal structures revealed a convergent mode of binding for diverse antibodies to the same CD4-binding-site epitope. A functional genomics analysis of expressed heavy and light chains revealed common pathways of antibody-heavy chain maturation, confined to the IGHV1-2*02 lineage, involving dozens of somatic changes, and capable of pairing with different light chains. Broadly neutralizing HIV-1 immunity associated with VRC01-like antibodies thus involves the evolution of antibodies to a highly affinity-matured state required to recognize an invariant viral structure, with lineages defined from thousands of sequences providing a genetic roadmap of their development.     

Two new IncRNAs regulate the key immune factor NOD1 and TRAF5 in chicken lymphocyte

Reticuloendotheliosis virus (REV) causes the atrophy of immune organs and immuno-suppression in chickens, but the underlying molecular mechanism of the immune response after infection by REV is not well understood. Presently, the RNA-seq was used to analyze the regulation of immune response to REV in chicken lymphocytes from peripheral blood. Overall, 134 differentially expressed long non-coding RNAs (lncRNAs) between cells with REV infection or without in vitro were screened. Based on the differentially expressed protein-coding genes, the nucleotide-binding oligomerization domain (NOD)-like receptor pathway related to immune regulation was enriched. Two lncRNAs (L11530 and L09863) were predicted to target the NOD1 and tumor necrosis factor receptor-associated factor 5 (TRAF5) gene, respectively, which are involved in the NOD-like receptor pathway with cis-regulation way. The in vitro results revealed the significantly up-regulated (P<0.01) levels of lncRNA-L11530 and its target gene, NOD1, and the significantly down-regulated (P<0.05) levels of lncRNA-L09863 and its target gene, TRAF5, in lymphocytes after REV infection. These changes also occurred in vivo in blood lymphocytes of chickens infected with REV. Further, L09863 and L11530 were respectively interfered, the expression levels of their target genes NOD1 or TRAF5 were significantly down-regulated, accompanied by the change of IL-8 and IL-18 secretions in lymphocytes. The NOD-like receptor pathway appears to be important in the immune response to REV, LncRNA-11530 and IncRNA-09863 might involve in the immune regulation on REV infection by targeting NOD1 or TRAF5 in blood lymphocytes of chickens. Our findings reveal a new regulation of lncRNAs (L11530 and L09863) on immunity in chicken peripheral blood lymphocytes for REV infection by changing the expression of the target genes via the NOD-like receptor pathway.     

DISC1 and PDE4B are interacting genetic factors in schizophrenia that regulate cAMP signaling

The disrupted in schizophrenia 1 (DISC1) gene is a candidate susceptibility factor for schizophrenia, but its mechanistic role in the disorder is unknown. Here we report that the gene encoding phosphodiesterase 4B (PDE4B) is disrupted by a balanced translocation in a subject diagnosed with schizophrenia and a relative with chronic psychiatric illness. The PDEs inactivate adenosine 3',5'-monophosphate (cAMP), a second messenger implicated in learning, memory, and mood. We show that DISC1 interacts with the UCR2 domain of PDE4B and that elevation of cellular cAMP leads to dissociation of PDE4B from DISC1 and an increase in PDE4B activity. We propose a mechanistic model whereby DISC1 sequesters PDE4B in resting cells and releases it in an activated state in response to elevated cAMP.     

DNA amplification for direct detection of HIV-1 in DNA of peripheral blood mononuclear cells

By means of a selective DNA amplification technique called polymerase chain reaction, proviral sequences of the human immunodeficiency virus (HIV-1) were identified directly in DNA isolated from peripheral blood mononuclear cells (PBMCs) of persons seropositive but not in DNA isolated from PBMCs of persons seronegative for the virus. Primer pairs from multiple regions of the HIV-1 genome were used to achieve maximum sensitivity of provirus detection. HIV-1 sequences were detected in 100% of DNA specimens from seropositive, homosexual men from whom the virus was isolated by coculture, but in none of the DNA specimens from a control group of seronegative, virus culture-negative persons. However, HIV-1 sequences were detected in 64% of DNA specimens from seropositive, virus culture-negative homosexual men. This method of DNA amplification made it possible to obtain results within 3 days, whereas virus isolation takes up to 3 to 4 weeks. The method may therefore be used to complement or replace virus isolation as a routine means of determining HIV-1 infection.     

RNA and protein in nucleolar structures of dragonfly oocytes

Dragonfly and damselfly oocytes regularly contain two nucleolus like bodies of different sizes, a primary nucleolus and a secondary nucleolus. The primary nucleolus stains more deeply with RNA stains than with an arginine stain; the seconidary nuicleolus stains conzversely. The primary nulcleolus incorporates uridine under all conditions tested; the secondary, only after precautions have been taken to preserve soluble RNA. Both inicorporate lysine.