The intensities of bands were determined by imagej software

In this study, we show an ingenious strategy of translational control of viral regulatory protein using host factors. Although BDV X and P have opposing effects in terms of viral polymerase activity, the translational regulation of X/P polycistronic mRNA has not been elucidated. Among them, the 0.8 kb X/P mRNA encodes at least three open reading frames (ORFs), upstream ORF, X, and P. BDV expresses mRNAs as polycistronic coding transcripts.

Borna disease virus (BDV) is a highly neurotropic RNA virus which is characterized by persistent infection. Translation regulation of viral mRNA is a good example of this. Therefore, the replication strategies of viruses may provide not only the understanding of virus pathogenesis but also useful models to disentangle the complex machinery of host cells. Our results not only demonstrate a unique translational control of viral regulatory protein, but also elucidate a previously unknown mechanism of regulation of polycistronic mRNA translation using RNA helicases.ДЄll viruses rely on host cell factors to complete their life cycles. We found that P may enhance ribosomal reinitiation at the X ORF by inhibition of the interaction of the DEAD-box RNA helicase DDX21 with the 5вЂІ untranslated region of X/P mRNA, via interference with its phosphorylation. Transient transfection of cDNA clones corresponding to the X/P mRNA revealed that the X ORF is translated predominantly by uORF-termination-coupled reinitiation, the efficiency of which is upregulated by expression of P.

Here we demonstrate that the X/P mRNA autogenously regulates the translation of X via interaction with host factors. However, the translation mechanism used by the X/P polycistronic mRNA has not been determined in detail.

The X is a negative regulator of viral polymerase activity, while the P phosphoprotein is a necessary cofactor of the polymerase complex, suggesting that the translation of X is controlled rigorously, depending on viral replication. The shortest transcript of BDV, X/P mRNA, encodes at least three open reading frames (ORFs): upstream ORF (uORF), X, and P in the 5вЂІ to 3вЂІ direction. Other than this historical reason, there is no purpose served by this inversion of the y coordinate.Borna disease virus (BDV) is a nonsegmented, negative-strand RNA virus that employs several unique strategies for gene expression. The beam scanned from left to right and top to bottom. Why is the coordinate system flipped vertically? Originally, digital images were defined in terms of the electron beam scanning pattern of televisions. Compared to normal mathematic convention, the origin is in the top left corner and the y coordinate is flipped. The coordinate system of image matrices defines x as increasing from left to right and y as increasing from top to bottom. To refer to a specific pixel within the image matrix, we define its coordinate at x and y. Thus the pixel array is a matrix of M columns x N rows. The image width is the number of columns, and the image height is the number of rows in the array. The size of an image is determined by the dimensions of this pixel array. Typically, pixels are organized in an ordered rectangular array. Digital images are made of picture elements called pixels. I'll skip explaining what a picture is and begin defining a digital image.

The intensities of bands were determined by imagej software