All Publications

  • Denoising of Aligned Genomic Data. Scientific reports Fischer-Hwang, I., Ochoa, I., Weissman, T., Hernaez, M. 2019; 9 (1): 15067


    Noise in genomic sequencing data is known to have effects on various stages of genomic data analysis pipelines. Variant identification is an important step of many of these pipelines, and is increasingly being used in clinical settings to aid medical practices. We propose a denoising method, dubbed SAMDUDE, which operates on aligned genomic data in order to improve variant calling performance. Denoising human data with SAMDUDE resulted in improved variant identification in both individual chromosome as well as whole genome sequencing (WGS) data sets. In the WGS data set, denoising led to identification of almost 2,000 additional true variants, and elimination of over 1,500 erroneously identified variants. In contrast, we found that denoising with other state-of-the-art denoisers significantly worsens variant calling performance. SAMDUDE is written in Python and is freely available at .

    View details for DOI 10.1038/s41598-019-51418-z

    View details for PubMedID 31636330

  • Estimating the Fundamental Limits Is Easier Than Achieving the Fundamental Limits IEEE TRANSACTIONS ON INFORMATION THEORY Jiao, J., Han, Y., Fischer-Hwang, I., Weissman, T. 2019; 65 (10): 6704–15
  • Observation of long-range tertiary interactions during ligand binding by the TPP riboswitch aptamer. eLife Duesterberg, V. K., Fischer-Hwang, I. T., Perez, C. F., Hogan, D. W., Block, S. M. 2015; 4


    The thiamine pyrophosphate (TPP) riboswitch is a cis-regulatory element in mRNA that modifies gene expression in response to TPP concentration. Its specificity is dependent upon conformational changes that take place within its aptamer domain. Here, the role of tertiary interactions in ligand binding was studied at the single-molecule level by combined force spectroscopy and Förster resonance energy transfer (smFRET), using an optical trap equipped for simultaneous smFRET. The 'Force-FRET' approach directly probes secondary and tertiary structural changes during folding, including events associated with binding. Concurrent transitions observed in smFRET signals and RNA extension revealed differences in helix-arm orientation between two previously-identified ligand-binding states that had been undetectable by spectroscopy alone. Our results show that the weaker binding state is able to bind to TPP, but is unable to form a tertiary docking interaction that completes the binding process. Long-range tertiary interactions stabilize global riboswitch structure and confer increased ligand specificity.

    View details for DOI 10.7554/eLife.12362

    View details for PubMedID 26709838

    View details for PubMedCentralID PMC4775224