The N-Terminal Region of the PA Subunit of the RNA Polymerase of Influenza A/HongKong/156/97 (H5N1) Influences Promoter Binding

BACKGROUND: The RNA polymerase of influenza virus is a heterotrimeric complex of PB1, PB2 and PA subunits which cooperate in the transcription and replication of the viral genome. Previous research has shown that the N-terminal region of the PA subunit of influenza A/WSN/33 (H1N1) virus is involved in promoter binding. METHODOLOGY/PRINCIPAL FINDINGS: Here we extend our studies of the influenza RNA polymerase to that of influenza strains A/HongKong/156/97 (H5N1) and A/Vietnam/1194/04 (H5N1). Both H5N1 strains, originally isolated from patients in 1997 and 2004, showed significantly higher polymerase activity compared with two classical human strains, A/WSN/33 (H1N1) and A/NT/60/68 (H3N2) in vitro. This increased polymerase activity correlated with enhanced promoter binding. The N-terminal region of the PA subunit was the major determinant of this enhanced promoter activity. CONCLUSIONS/SIGNIFICANCE: Overall we suggest that the N-terminal region of the PA subunit of two recent H5N1 strains can influence promoter binding and we speculate this may be a factor in their virulence

Overexpression of TIFY genes promotes plant growth in rice through jasmonate signaling

<p>Because environmental stress can reduce crop growth and yield, the identification of genes that enhance agronomic traits is increasingly important. Previous screening of full-length cDNA overexpressing (FOX) rice lines revealed that OsTIFY11b, one of 20 TIFY proteins in rice, affects plant size, grain weight, and grain size. Therefore, we analyzed the effect of <i>OsTIFY11b</i> and nine other TIFY genes on the growth and yield of corresponding TIFY-FOX lines. Regardless of temperature, grain weight and culm length were enhanced in lines overexpressing TIFY11 subfamily genes, except <i>OsTIFY11e.</i> The TIFY-FOX plants exhibited increased floret number and reduced days to flowering, as well as reduced spikelet fertility, and <i>OsTIFY10b</i>, in particular, enhanced grain yield by minimizing decreases in fertility. We suggest that the enhanced growth of TIFY-transgenic rice is related to regulation of the jasmonate signaling pathway, as in <i>Arabidopsis.</i> Moreover, we discuss the potential application of TIFY overexpression for improving crop yield.</p