PubMed Health⌕ Search

Biomedical subjects

Hongyan Xing

Publications and source records attributed to Hongyan Xing.

4 recordsLinked to original sources
PubMed2005

Increased pathogen resistance and yield in transgenic plants expressing combinations of the modified antimicrobial peptides based on indolicidin and magainin.

Reverse peptide of indolicidin (Rev4), a 13-residue peptide based on the sequence of indolicidin, has been shown to possess both strong antimicrobial and protease inhibitory activities in vitro. To evaluate its efficacy in vivo, we produced and evaluated transgenic tobacco (Nicotiana tabacum L.) and Arabidopsis thaliana [(L.) Heynh.] plants expressing Rev4 with different signal peptide sequences for pathogen resistance. All transgenic plants showed normal growth and development, an indication of no or low cytotoxicity of the peptide. Furthermore, the transgenic plants exhibited elevated resistance to three bacterial and two oomycete pathogens. Interestingly, tobacco plants expressing Rev4 displayed enhanced yield compared to the control as indicated by an increased biomass production by as much as 34% in two field trials. When Rev4 was coexpressed with another antimicrobial peptide, Myp30, the disease resistance levels in the transgenic Arabidopsis were enhanced. These findings suggest the potential of using these peptides to protect plants from microbial pathogens and to enhance yield.

Anti-Infective Agents↗
PubMed2005

Mechanism of hsp70i gene bookmarking.

In contrast to most genomic DNA in mitotic cells, the promoter regions of some genes, such as the stress-inducible hsp70i gene that codes for a heat shock protein, remain uncompacted, a phenomenon called bookmarking. Here we show that hsp70i bookmarking is mediated by a transcription factor called HSF2, which binds this promoter in mitotic cells, recruits protein phosphatase 2A, and interacts with the CAP-G subunit of the condensin enzyme to promote efficient dephosphorylation and inactivation of condensin complexes in the vicinity, thereby preventing compaction at this site. Blocking HSF2-mediated bookmarking by HSF2 RNA interference decreases hsp70i induction and survival of stressed cells in the G1 phase, which demonstrates the biological importance of gene bookmarking.

Adenosine Triphosphatases↗
PubMed2004

HSF1 modulation of Hsp70 mRNA polyadenylation via interaction with symplekin.

Induction of heat shock protein (HSP) gene expression by stress is initiated by binding of HSF1 to HSP gene promoters to increase their transcription. The cytoprotective functions of these HSPs are essential for cell survival, and thus it is critical that inducible HSP gene expression be executed rapidly and efficiently. Here we report an interaction between heat shock factor 1 (HSF1) and symplekin, a protein known to form a complex with the polyadenylation factors CstF and CPSF. HSF1-symplekin complexes are detected only after stress treatment, and these two proteins co-localize in punctate nuclear structures in stressed cells. HSF1 also complexes in a stress-induced manner with the 3' processing factor CstF-64. Interfering with HSF1-symplekin interaction by overexpressing a non-DNA-binding mutant HSF1 protein significantly decreases Hsp70 mRNA polyadenylation in stressed cells, supporting the functional role for HSF1 in promoting 3' processing of this transcript. Importantly, this was also found to result in a significant loss of Hsp70 protein induction and increased cell death in response to stress exposure. These results indicate that the HSF1-symplekin interaction functions as a mechanism for recruiting polyadenylation factors to HSP genes to enhance the efficiency/kinetics of production of mature Hsp mRNA transcripts to achieve the critical cellular need for rapid HSP expression after stress. Thus, HSF1 regulates HSP gene expression at not one but two different steps of the expression pathway, functioning both as a transcription factor and a polyadenylation stimulatory factor.

Animals↗