Browsing by Author "Lee, Jung-Youn"
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Item Facilitating viral vector movement enhances heterologous protein production in an established plant system(Plant Biotechnology Journal, 2023-01-04) Wang, Xu; Prokhnevsky, Alexei I.; Skarjinskaia, Marina; Razzak, Md Abdur; Streatfield, Stephen J.; Lee, Jung-YounMolecular farming technology using transiently transformed Nicotiana plants offers an economical approach to the pharmaceutical industry to produce an array of protein targets including vaccine antigens and therapeutics. It can serve as a desirable alternative approach for those proteins that are challenging or too costly to produce in large quantities using other heterologous protein expression systems. However, since cost metrics are such a critical factor in selecting a production host, any system-wide modifications that can increase recombinant protein yields are key to further improving the platform and making it applicable for a wider range of target molecules. Here, we report on the development of a new approach to improve target accumulation in an established plant-based expression system that utilizes viral-based vectors to mediate transient expression in Nicotiana benthamiana. We show that by engineering the host plant to support viral vectors to spread more effectively between host cells through plasmodesmata, protein target accumulation can be increased by up to approximately 60%.Item Improving Inter-Helix Contact Prediction With Local 2D Topological Information(IEEE/ACM Transactions on Computational Biology and Bioinformatics, 2023-05-08) Li, Jiefu; Sawhney, Aman; Lee, Jung-Youn; Liao, LiInter-helix contact prediction is to identify residue contact across different helices in α-helical integral membrane proteins. Despite the progress made by various computational methods, contact prediction remains as a challenging task, and there is no method to our knowledge that directly tap into the contact map in an alignment free manner. We build 2D contact models from an independent dataset to capture the topological patterns in the neighborhood of a residue pair depending it is a contact or not, and apply the models to the state-of-art method's predictions to extract the features reflecting 2D inter-helix contact patterns. A secondary classifier is trained on such features. Realizing that the achievable improvement is intrinsically hinged on the quality of original predictions, we devise a mechanism to deal with the issue by introducing, 1) partial discretization of original prediction scores to more effectively leverage useful information 2) fuzzy score to assess the quality of the original prediction to help with selecting the residue pairs where improvement is more achievable. The cross-validation results show that the prediction from our method outperforms other methods including the state-of-the-art method (DeepHelicon) by a notable degree even without using the refinement selection scheme. By applying the refinement selection scheme, our method outperforms the state-of-the-art method significantly in these selected sequences.Item pGenN, a Gene Normalization Tool for Plant Genes and Proteins in Scientific Literature(PLOS (Public Library of Science), 2015-08-10) Ding, Ruoyao; Arighi, Cecilia N.; Lee, Jung-Youn; Wu, Cathy H.; Vijay-Shanker, K.; Ruoyao Ding, Cecilia N. Arighi, Jung-Youn Lee, Cathy H. Wu, K. Vijay-Shanker; Ding, Ruoyao; Arighi, Cecilia N.; Lee, Jung-Youn; Wu, Cathy H.; Vijay-Shanker, K.BACKGROUND Automatically detecting gene/protein names in the literature and connecting them to databases records, also known as gene normalization, provides a means to structure the information buried in free-text literature. Gene normalization is critical for improving the coverage of annotation in the databases, and is an essential component of many text mining systems and database curation pipelines. METHODS In this manuscript, we describe a gene normalization system specifically tailored for plant species, called pGenN (pivot-based Gene Normalization). The system consists of three steps: dictionary-based gene mention detection, species assignment, and intra species normalization. We have developed new heuristics to improve each of these phases. RESULTS We evaluated the performance of pGenN on an in-house expertly annotated corpus consisting of 104 plant relevant abstracts. Our system achieved an F-value of 88.9%(Precision 90.9% and Recall 87.2%) on this corpus, outperforming state-of-art systems presented in BioCreative III. We have processed over 440,000 plant-related Medline abstracts using pGenN. The gene normalization results are stored in a local database for direct query from the pGenN web interface (proteininformationresource.org/pgenn/). The annotated literature corpus is also publiclyItem pGenN, a Gene Normalization Tool for Plant Genes and Proteins in Scientific Literature(Public Library of Science, 2015-08-10) Ding, Ruoyao; Arighi, Cecilia N.; Lee, Jung-Youn; Wu, Cathy H.; Vijay-Shanker, K.; Ruoyao Ding, Cecilia N. Arighi, Jung-Youn Lee, Cathy H. Wu, K. Vijay-Shanker; Dina, Ruoyao; Arighi, Cecilia N.; Lee, Jung-Youn; Wu, Cathy H.; Vijay-Shanker, K.BACKGROUND Automatically detecting gene/protein names in the literature and connecting them to databases records, also known as gene normalization, provides a means to structure the information buried in free-text literature. Gene normalization is critical for improving the coverage of annotation in the databases, and is an essential component of many text mining systems and database curation pipelines. METHODS In this manuscript, we describe a gene normalization system specifically tailored for plant species, called pGenN (pivot-based Gene Normalization). The system consists of three steps: dictionary-based gene mention detection, species assignment, and intra species normalization. We have developed new heuristics to improve each of these phases. RESULTS We evaluated the performance of pGenN on an in-house expertly annotated corpus consisting of 104 plant relevant abstracts. Our system achieved an F-value of 88.9%(Precision 90.9% and Recall 87.2%) on this corpus, outperforming state-of-art systems presented in BioCreative III. We have processed over 440,000 plant-related Medline abstracts using pGenN. The gene normalization results are stored in a local database for direct query from the pGenN web interface (proteininformationresource.org/pgenn/). The annotated literature corpus is also publicly available through the PIR text mining portal (proteininformationresource. org/iprolink/).Item Phloem unloading in Arabidopsis roots is convective and regulated by the phloem- pole pericycle(eLIFE Sciences Publications, 2017-02-23) Ross-Elliott, Timothy J.; Jensen, Kaare H.; Haaning, Katrine S.; Wager, Brittney M.; Knoblauch, Jan; Howell, Alexander H.; Mullendore, Daniel L.; Monteith, Alexander G.; Paultre, Danae; Yan, Dawei; Otero, Sofia; Bourdon, Matthieu; Sager, Ross; Lee, Jung-Youn; Helariutta, Yka¨; Knoblauch, Michael; Oparka, Karl J.; Timothy J Ross-Elliott, Kaare H Jensen, Katrine S Haaning, Brittney M Wager, Jan Knoblauch, Alexander H Howell, Daniel L Mullendore, Alexander G Monteith, Danae Paultre, Dawei Yan, Sofia Otero, Matthieu Bourdon, Ross Sager, Jung-Youn Lee, Yka¨ Helariutta, Michael Knoblauch, Karl J Oparka; Sager, Ross; Lee, Jung-YounIn plants, a complex mixture of solutes and macromolecules is transported by the phloem. Here, we examined how solutes and macromolecules are separated when they exit the phloem during the unloading process. We used a combination of approaches (non-invasive imaging, 3D-electron microscopy, and mathematical modelling) to show that phloem unloading of solutes in Arabidopsis roots occurs through plasmodesmata by a combination of mass flow and diffusion (convective phloem unloading). During unloading, solutes and proteins are diverted into the phloem-pole pericycle, a tissue connected to the protophloem by a unique class of ‘funnel plasmodesmata’. While solutes are unloaded without restriction, large proteins are released through funnel plasmodesmata in discrete pulses, a phenomenon we refer to as ‘batch unloading’. Unlike solutes, these proteins remain restricted to the phloem-pole pericycle. Our data demonstrate a major role for the phloem-pole pericycle in regulating phloem unloading in roots.Item Targeting of plasmodesmal proteins requires unconventional signals(The Plant Cell, 2023-08-02) Luna, Gabriel Robles; Li, Jiefu; Wang, Xu; Liao, Li; Lee, Jung-YounEffective cellular signaling relies on precise spatial localization and dynamic interactions among proteins in specific subcellular compartments or niches, such as cell-to-cell contact sites and junctions. In plants, endogenous and pathogenic proteins gained the ability to target plasmodesmata, membrane-lined cytoplasmic connections, through evolution to regulate or exploit cellular signaling across cell wall boundaries. For example, the receptor-like membrane protein PLASMODESMATA-LOCATED PROTEIN 5 (PDLP5), a potent regulator of plasmodesmal permeability, generates feed-forward or feed-back signals important for plant immunity and root development. However, the molecular features that determine the plasmodesmal association of PDLP5 or other proteins remain largely unknown, and no protein motifs have been identified as plasmodesmal targeting signals. Here, we developed an approach combining custom-built machine-learning algorithms and targeted mutagenesis to examine PDLP5 in Arabidopsis thaliana and Nicotiana benthamiana. We report that PDLP5 and its closely related proteins carry unconventional targeting signals consisting of short stretches of amino acids. PDLP5 contains 2 divergent, tandemly arranged signals, either of which is sufficient for localization and biological function in regulating viral movement through plasmodesmata. Notably, plasmodesmal targeting signals exhibit little sequence conservation but are located similarly proximal to the membrane. These features appear to be a common theme in plasmodesmal targeting.