Associate
Zunyi Yang

Education

BS in Chemistry. Northwest University, China (1997)
PhD in Chemistry. Shanghai Institute of Organic Chemistry (2002)
Postdoctoral Research Associate. University of Florida (2005)

Research summary

My research focuses on the development of an efficient and accurate method for the detection of multiple nucleic acids in biological sample. This innovative technology is the multiplexed amplification of DNA and RNA and the orthogonal capture of oligonucleotides tagged with non-standard nucleobases in such a fashion where close mismatches do not compete. My research includes: 1) Synthesis of two components of a non-standard nucleobase pair, dZ:dP, along with a demonstration that the stability of the dZ:dP base pair is stronger than G:C base pair. Furthermore, a demonstration to show the ability of each base to effectively discriminate against mismatches in short duplex DNA. 2) PCR amplification of DNA containing dZ:dP base pair with sufficient fidelity and development of the methodology for the measurement of enzyme fidelity. 3) Synthesis of a novel molecular beacon containing dZ and dP to detect the level of the expression of viral genes in cancer cell. 4) Development of the technology of multiplexed PCR and microarray of dZ and dP, by combining the enzymology and chemistry of non-standard nucleobases. The goal of my research is to reduce the cost of personalized DNA sequencing, revolutionize the diagnosis, management, and treatment of human disease.

Recent Publications

Functional Selection of Tau Oligomerization-Inhibiting Aptamers
Bang Wang, Xiaoshu Pan, I-Ting Teng, Xiaowei Li, Firas Kobeissy, Zo-Yu Wu, Jiepei Zhu, Guangzheng Cai, He Yan, Xin Yan, Mingwei Liang, Fahong Yu, Zunyi Yang, Elisa Biondi, William Haskins, Y. Charles Cao, Steven A. Benner, Weihong Tan, Kevin Wang
Angew. Chem. Int. Ed. (2024) e202402007, https://doi.org/10.1002/anie.202402007
<Abstract>

Pathological hyperphosphorylation and aggregation of microtubule-associated Tau protein contribute to Alzheimer's Disease (AD) and other related tauopathies. Currently, no cure exists for Alzheimer's Disease. Aptamers offer significant potential as next-generation therapeutics in biotechnology and the treatment of neurological disorders. Traditional aptamer selection methods for Tau protein focus on binding affinity rather than interference with pathological Tau. In this study, we developed a new selection strategy to enrich DNA aptamers that bind to surviving monomeric Tau protein under conditions that would typically promote Tau aggregation. Employing this approach, we identified a set of aptamer candidates. Notably, BW1c demonstrates a high binding affinity (Kd = 6.6 nM) to Tau protein and effectively inhibits arachidonic acid (AA)-induced Tau protein oligomerization and aggregation. Additionally, it inhibits GSK3β-mediated Tau hyperphosphorylation in cell-free systems and okadaic acid-mediated Tau hyperphosphorylation in cellular milieu. Lastly, retro-orbital injection of BW1c tau aptamer shows the ability to cross the blood brain barrier and gain access to neuronal cell body. Through further refinement and development, these Tau aptamers may pave the way for a first-in-class neurotherapeutic to mitigate tauopathy-associated neurodegenerative disorders.

Enzyme-assisted high throughput sequencing of an expanded genetic alphabet at single base resolution
Bang Wang, Kevin M. Bradley, Myong-Jung Kim, Roberto Laos, Cen Chen, Dietlind L. Gerloff, Luran Manfio, Zunyi Yang & Steven A. Benner
Nat. Commun.15(4057), Nature (2024) https://doi.org/10.1038/s41467-024-48408-9
<Abstract>

With just four building blocks, low sequence information density, few functional groups, poor control over folding, and difficulties in forming compact folds, natural DNA and RNA have been disappointing platforms from which to evolve receptors, ligands, and catalysts. Accordingly, synthetic biology has created "artificially expanded genetic information systems" (AEGIS) to add nucleotides, functionality, and information density. With the expected improvements seen in AegisBodies and AegisZymes, the task for synthetic biologists shifts to developing for expanded DNA the same analytical tools available to natural DNA. Here we report one of these, an enzyme-assisted sequencing of expanded genetic alphabet (ESEGA) method to sequence six-letter AEGIS DNA. We show how ESEGA analyses this DNA at single base resolution, and applies it to optimized conditions for six-nucleotide PCR, assessing the fidelity of various DNA polymerases, and extending this to AEGIS components with functional groups. This supports the renewed exploitation of expanded DNA alphabets in biotechnology.

A folding motif formed with an expanded genetic alphabet
Bang Wang, James R. Rocca, Shuichi Hoshika, Cen Chen, Zunyi Yang, Reza Esmaeeli, Jianguo Wang, Xiaoshu Pan, Jianrong Lu, Kevin K. Wang, Y. Charles Cao, Weihong Tan & Steven A. Benner
Nat. Chem., Nature (2024) https://doi.org/10.1038/s41557-024-01552-7
<Abstract>

Adding synthetic nucleotides to DNA increases the linear information density of DNA molecules. Here we report that it also can increase the diversity of their three-dimensional folds. Specifically, an additional nucleotide (dZ, with a 5-nitro-6-aminopyridone nucleobase), placed at twelve sites in a 23-nucleotides-long DNA strand, creates a fairly stable unimolecular structure (that is, the folded Z-motif, or fZ-motif) that melts at 66.5°C at pH 8.5. Spectroscopic, gel and two-dimensional NMR analyses show that the folded Z-motif is held together by six reverse skinny dZ^-:dZ base pairs, analogous to the crystal structure of the free heterocycle. Fluorescence tagging shows that the dZ^-:dZ pairs join parallel strands in a four-stranded compact down-up-down-up fold. These have two possible structures: one with intercalated dZ^-:dZ base pairs, the second without intercalation. The intercalated structure would resemble the i-motif formed by dC:dC⁺-reversed pairing at pH ≤ 6.5. This fZ-motif may therefore help DNA form compact structures needed for binding and catalysis.

Ultra-rapid detection of SARS-CoV-2 in public workspace environments
Yaren, O., McCarter, J., Phadke, N., Bradley, K. M., Overton, B., Yang, Z., Ranade, S., Patil, K., Bangale, R., Benner, S. A.
PLOS One, Public Library of Science (2021) 10.1371/journal.pone.0240524, DOI:10.1101/2020.09.29.20204131
<Abstract>

Managing the pandemic caused by SARS-CoV-2 requires new capabilities in testing, including the possibility of identifying, in minutes, infected individuals as they enter spaces where they must congregate in a functioning society, including workspaces, schools, points of entry, and commercial business establishments. Here, the only useful tests (a) require no sample transport, (b) require minimal sample manipulation, (c) can be performed by unlicensed individuals, (d) return results on the spot in much less than one hour, and (e) cost no more than a few dollars. The sensitivity need not be as high as normally required by the FDA for screening asymptomatic carriers (as few as 10 virions per sample), as these viral loads are almost certainly not high enough for an individual to present a risk for forward infection. This allows tests specifically useful for this pandemic to trade-off unneeded sensitivity for necessary speed, simplicity, and frugality. In some studies, it was shown that viral load that creates forward-infection risk may exceed 10⁵ virions per milliliter, easily within the sensitivity of an RNA amplification architecture, but unattainable by antibody-based architectures that simply target viral antigens. Here, we describe such a test based on a displaceable probe loop amplification architecture.

An Aptamer-Nanotrain Assembled from Six-Letter DNA Delivers Doxorubicin Selectively to Liver Cancer Cells.
Zhang, L., Wang, S., Yang, Z., Hoshika, S., Xie, S., Li, J., Chen, X., Wan, S., Li, L., Benner, S.A., Tan, W.
Angew. Chem. Int. Ed. (2020) 59(2): 663-668, DOI:10.1002/anie.201909691
<Abstract>

Expanding the number of nucleotides in DNA increases the information density of functional DNA molecules, creating nanoassemblies that cannot be invaded by natural DNA/RNA in complex biological systems. Here, we show how six-letter GACTZP DNA contributes this property in two parts of a nanoassembly: (1) in an aptamer evolved from a six-letter DNA library to selectively bind liver cancer cells; and (2) in a six-letter self-assembling GACTZP nanotrain that carries the drug doxorubicin. The aptamer-nanotrain assembly, charged with doxorubicin, selectively kills liver cancer cells in culture, as the selectivity of the aptamer binding directs doxorubicin into the aptamer-targeted cells. The assembly does not kill untransformed cells that the aptamer does not bind. This architecture, built with an expanded genetic alphabet, is reminiscent of antibodies conjugated to drugs, which presumably act by this mechanism as well, but with the antibody replaced by an aptamer.

Ligand Guided Selection (LIGS) with Artificially Expanded Genetic Information Systems against TCR-CD3ε
Zumrut, H., Yang, Z., Williams, N., Arizala, J., Batool, S., Benner, S.A., Mallikaratchy, P.
Biochemistry, ACS (2020) 59(4):552-562, DOI:10.1021/acs.biochem.9b00919
<Abstract>

Here we are reporting, for the first time, a ligand-guided selection (LIGS) experiment using an artificially expanded genetic information system (AEGIS) to successfully identify an AEGIS–DNA aptamer against T cell receptor-CD3ε expressed on Jurkat.E6 cells. Thus, we have effectively combined the enhanced diversity of an AEGIS DNA library with LIGS to develop a superior screening platform to discover superior aptamers. Libraries of DNA molecules from highly diversified building blocks will provide better ligands due to more functional diversity and better-controlled folding. Thus, a DNA library with AEGIS components (dZ and dP) was used in LIGS experiments against TCR-CD3ε in its native state using two clinically relevant monoclonal antibodies to identify an aptamer termed JZPO-10, with nanomolar affinity. Multiple specificity assays using knockout cells, and competition experiments using monoclonal antibodies utilized in LIGS, show unprecedented specificity of JZPO-10, suggesting that the combination of LIGS with AEGIS-DNA libraries will provide a superior screening platform to discover artificial ligands against critical cellular targets.

Eliminating Primer Dimers and Improving SNP detection using Self-Avoiding Molecular Recognition Systems (SAMRS)
Yang, Z., Le, J.T., Hutter, D., Bradley, K.M., Overton, B.R., McLendon, C., Benner, S.A.
Biol. Methods Protoc., Oxford Academics (2020) 5(1):bpaa004, DOI:10.1093/biomethods/bpaa004
<Abstract>

Despite its widespread value to molecular biology, the polymerase chain reaction (PCR) encounters modes that unproductively consume PCR resources and prevent clean signals, especially when high sensitivity, high SNP discrimination, and high multiplexing are sought. Here, we show how "self-avoiding molecular recognition systems" (SAMRS) manage such difficulties. SAMRS nucleobases pair with complementary nucleotides with strengths comparable to the A:T pair, but do not pair with other SAMRS nucleobases. This should allow primers holding SAMRS components to avoid primer-primer interactions, preventing primer dimers, allowing more sensitive SNP detection, and supporting higher levels of multiplex PCR. The experiments here examine the PCR performances of primers containing different numbers of SAMRS components placed strategically at different positions, and put these performances in the context of estimates of SAMRS:standard pairing strengths. The impact of these variables on primer dimer formation, the overall efficiency and sensitivity of SAMRS-based PCR, and the value of SAMRS primers when detecting single nucleotide polymorphisms (SNPs) are also evaluated. With appropriately chosen polymerases, SNP discrimination can be greater than the conventional allele-specific PCR, with the further benefit of avoiding primer dimer artifacts. General rules guiding the design of SAMRS-modified primers are offered to support medical research and clinical diagnostics products.

Nucleoside analogs to manage sequence divergence in nucleic acid amplification and SNP detection.
Yang, Z., Kim, H.-J., Le, J., McLendon, C., Bradley, K.M., Kim, M.-S., Hutter, D., Hoshika, S., Yaren, O., Benner, S.A.
Nucl. Acids Res. (2018) 46(12): 5902-10,DOI:10.1093/nar/gky392
<Abstract>

Described here are the synthesis, enzymology and some applications of a purine nucleoside analog (H) designed to have two tautomeric forms, one complementary to thymidine (T), the other complementary to cytidine (C). The performance of H is compared by various metrics to performances of other 'biversal' analogs that similarly rely on tautomerism to complement both pyrimidines. These include (i) the thermodynamic stability of duplexes that pair these biversals with various standard nucleotides, (ii) the ability of the biversals to support polymerase chain reaction (PCR), (iii) the ability of primers containing biversals to equally amplify targets having polymorphisms in the primer binding site, and (iv) the ability of ligation-based assays to exploit the biversals to detect medically relevant single nucleotide polymorphisms (SNPs) in sequences flanked by medically irrelevant polymorphisms. One advantage of H over the widely used inosine 'universal base' and 'mixed sequence' probes is seen in ligation-based assays to detect SNPs. The need to detect medically relevant SNPs within ambiguous sequences is especially important when probing RNA viruses, which rapidly mutate to create drug resistance, but also suffer neutral drift, the second obstructing simple methods to detect the first. Thus, H is being developed to detect variants of viruses that are rapidly mutating.

Biological phosphorylation of an Unnatural Base Pair (UBP) using a Drosophila melanogaster deoxynucleoside kinase (DmdNK) mutant.
Chen, F., Zhang, Y., Daugherty, A.B., Yang, Z.Y., Shaw, R., Dong, M.X., Lutz, S. and Benner, S.A.
PLOS One, Public Library of Science (2017) 12(3): e0174163, DOI:10.1371/journal.pone.0174163
<Abstract>

One research goal for unnatural base pair (UBP) is to replicate, transcribe and translate them in vivo. Accordingly, the corresponding unnatural nucleoside triphosphates must be available at sufficient concentrations within the cell. To achieve this goal, the unnatural nucleoside analogues must be phosphorylated to the corresponding nucleoside triphosphates by a cascade of three kinases. The first step is the monophosphorylation of unnatural deoxynucleoside catalyzed by deoxynucleoside kinases (dNK), which is generally considered the rate limiting step because of the high specificity of dNKs. Here, we applied a Drosophila melanogaster deoxyribonucleoside kinase (DmdNK) to the phosphorylation of an UBP (a pyrimidine analogue (6-amino-5-nitro-3-(1'-b-d-2'-deoxyribofuranosyl)-2(1H)-pyridone, Z) and its complementary purine analogue (2-amino-8-(1'-b-d-2'-deoxyribofuranosyl)-imidazo[1,2-a]-1,3,5-triazin-4(8H)-one, P). The results showed that DmdNK could efficiently phosphorylate only the dP nucleoside. To improve the catalytic efficiency, a DmdNK-Q81E mutant was created based on rational design and structural analyses. This mutant could efficiently phosphorylate both dZ and dP nucleoside. Structural modeling indicated that the increased efficiency of dZ phosphorylation by the DmdNK-Q81E mutant might be related to the three additional hydrogen bonds formed between E81 and the dZ base. Overall, this study provides a groundwork for the biological phosphorylation and synthesis of unnatural base pair in vivo.

Point of sampling detection of Zika virus within a multiplexed kit capable of detecting dengue and chikungunya
Yaren, O., Alto, B.W., Gangodkar, P.V., Ranade, S.R., Patil, K.N., Bradley, K.M., Yang, Z., Phadke, N., Benner, S.A
BMC Infect. Dis., BioMed Central Ltd. (2017) 17(1):293, DOI:10.1186/s12879-017-2382-0
<Abstract>

Background: Zika, dengue, and chikungunya are three mosquito-borne viruses having overlapping transmission vectors. They cause diseases having similar symptoms in human patients, but requiring different immediate management steps. Therefore, rapid (< one hour) discrimination of these three viruses in patient samples and trapped mosquitoes is needed. The need for speed precludes any assay that requires complex up-front sample preparation, such as extraction of nucleic acids from the sample. Also precluded in robust point-of-sampling assays is downstream release of the amplicon mixture, as this risks contamination of future samples that will give false positives.

Methods: Procedures are reported that directly test urine and plasma (for patient diagnostics) or crushed mosquito carcasses (for environmental surveillance). Carcasses are captured on paper samples carrying quaternary ammonium groups (Q-paper), which may be directly introduced into the assay. To avoid the time and instrumentation requirements of PCR, the procedure uses loop-mediated isothermal amplification (LAMP). Downstream detection is done in sealed tubes, with dTTP-dUTP mixtures in the LAMP with a thermolabile uracil DNA glycosylase (UDG); this offers a second mechanism to prevent forward contamination. Reverse transcription LAMP (RT-LAMP) reagents are distributed dry without requiring a continuous chain of refrigeration.

Results: The tests detect viral RNA in unprocessed urine and other biological samples, distinguishing Zika, chikungunya, and dengue in urine and in mosquitoes infected with live Zika and chikungunya viruses. The limits of detection (LODs) are ~0.71 pfu equivalent viral RNAs for Zika, ~1.22 pfu equivalent viral RNAs for dengue, and ~38 copies of chikungunya viral RNA. A handheld, battery-powered device with an orange filter was constructed to visualize the output. Preliminary data showed that this architecture, working with pre-prepared tubes holding lyophilized reagent/enzyme mixtures and shipped without a chain of refrigeration, also worked with human plasma samples to detect chikungunya and dengue in Pune, India.

Conclusions: A kit, complete with a visualization device, is now available for point-of-sampling detection of Zika, chikungunya, and dengue. The assay output is read in ca. 30 min by visualizing (human eye) three-color coded fluorescence signals. Assay in dried format allows it to be run in low-resource environments.

(View publication page for Zunyi Yang)

Associate
Zunyi Yang

Education

Research summary

Recent Publications

Interests

Contact

Associate Zunyi Yang

Education

Research summary

Recent Publications

Interests

Contact

Associate
Zunyi Yang