Chikungunya virus (CHIKV) is a reemerging alphavirus. Since 2005, it has infected millions of people during outbreaks in Africa, Asia, and South/Central America. CHIKV replication depends on host cell factors at many levels and is expected to have a profound effect on cellular physiology.
View Article and Find Full Text PDFProgrammed ribosomal frameshifting (PRF) is a mechanism used by arteriviruses like porcine reproductive and respiratory syndrome virus (PRRSV) to generate multiple proteins from overlapping reading frames within its RNA genome. PRRSV employs -1 PRF directed by RNA secondary and tertiary structures within its viral genome (canonical PRF), as well as a noncanonical -1 and -2 PRF that are stimulated by the interactions of PRRSV nonstructural protein 1β (nsp1β) and host protein poly(C)-binding protein (PCBP) 1 or 2 with the viral genome. Together, nsp1β and one of the PCBPs act as transactivators that bind a C-rich motif near the shift site to stimulate -1 and -2 PRF, thereby enabling the ribosome to generate two frameshift products that are implicated in viral immune evasion.
View Article and Find Full Text PDFTranslational control through programmed ribosomal frameshifting (PRF) is exploited widely by viruses and increasingly documented in cellular genes. Frameshifting is induced by mRNA secondary structures that compromise ribosome fidelity during decoding of a heptanucleotide 'slippery' sequence. The nsp2 PRF signal of porcine reproductive and respiratory syndrome virus is distinctive in directing both -2 and -1 PRF and in its requirement for a trans-acting protein factor, the viral replicase subunit nsp1β.
View Article and Find Full Text PDFChikungunya virus (CHIKV) is an arthropod-borne reemerging human pathogen that generally causes a severe persisting arthritis. Since 2005, the virus has infected millions of people during outbreaks in Africa, Indian Ocean Islands, Asia, and South/Central America. Many steps of the replication and expression of CHIKV's 12-kb RNA genome are highly dependent on cellular factors, which thus constitute potential therapeutic targets.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
May 2014
Programmed -1 ribosomal frameshifting (-1 PRF) is a widely used translational mechanism facilitating the expression of two polypeptides from a single mRNA. Commonly, the ribosome interacts with an mRNA secondary structure that promotes -1 frameshifting on a homopolymeric slippery sequence. Recently, we described an unusual -2 frameshifting (-2 PRF) signal directing efficient expression of a transframe protein [nonstructural protein 2TF (nsp2TF)] of porcine reproductive and respiratory syndrome virus (PRRSV) from an alternative reading frame overlapping the viral replicase gene.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
October 2012
Programmed -1 ribosomal frameshifting (-1 PRF) is a gene-expression mechanism used to express many viral and some cellular genes. In contrast, efficient natural utilization of -2 PRF has not been demonstrated previously in eukaryotic systems. Like all nidoviruses, members of the Arteriviridae (a family of positive-stranded RNA viruses) express their replicase polyproteins pp1a and pp1ab from two long ORFs (1a and 1b), where synthesis of pp1ab depends on -1 PRF.
View Article and Find Full Text PDFObjective: The aim of this study was to develop a pyrophosphorolysis-activated polymerization (PAP) assay for non-invasive prenatal diagnosis (NIPD) of β-thalassemia major and sickle-cell disease (SCD). PAP is able to detect mutations in free fetal DNA in a highly contaminating environment of maternal plasma DNA.
Methods: Pyrophosphorolysis-activated polymerization primers were designed for 12 informative SNPs, genotyped by melting curve analysis (MCA) in both parents.