Biology subjects

White, A. K.

Publications and source records attributed to White, A. K..

4 recordsLinked to original sources

bioRxiv2021

Structure-activity mapping of the force- and sequence-dependent landscape of T cell activation

Adaptive immunity relies on T lymphocytes that use {beta} T-cell receptors (TCRs) to discriminate amongst peptides presented by MHC molecules (pMHCs). An enhanced ability to screen for pMHCs capable of inducing robust T-cell responses could have broad applications in diagnosing and treating immune diseases. T cell activation relies on biomechanical forces to initiate triggering of the TCR. Yet, most in vitro screening technologies for antigenic peptides test potential pMHCs for T cell binding without force and thus are often not predictive of activating peptides. Here, we present a technology that uses biomechanical force to initiate T cell triggering in high throughput. BATTLES (Biomechanically-Assisted T-cell Triggering for Large-scale Exogenous-pMHC Screening) displays candidate pMHCs on spectrally encoded smart beads capable of applying physiological loads to T cells, facilitating exploration of the force- and sequence-dependent landscape of T-cell responses. BATTLES can be used to explore basic T-cell mechanobiology and T cell-based immunotherapies.

biophysics↗

bioRxiv2021

Trp53 ablation fails to prevent microcephaly in mouse pallium with impaired minor intron splicing

Mutations in minor spliceosome component RNU4ATAC, a small nuclear RNA (snRNA), are linked to primary microcephaly. We have reported that in the conditional knockout (cKO) mice for Rnu11, another minor spliceosome snRNA, minor intron splicing defect in minor intron-containing genes (MIGs) regulating cell cycle resulted in cell cycle defects, with a concomitant increase in {gamma}H2aX+ cells and p53-mediated apoptosis. Trp53 ablation in the Rnu11 cKO mice did not prevent microcephaly. However, RNAseq analysis of the double knockout (dKO) pallium reflected transcriptomic shift towards the control from the Rnu11 cKO. We found elevated minor intron retention and alternative splicing across minor introns in the dKO. Disruption of these MIGs resulted in cell cycle defects that were more severe and detected earlier in the dKO, but with delayed detection of {gamma}H2aX+ DNA damage. Thus, p53 might also play a role in causing DNA damage in the developing pallium. In all, our findings further refine our understanding of the role of the minor spliceosome in cortical development and identify MIGs underpinning microcephaly in minor spliceosome-related diseases.

developmental biology↗

bioRxiv2020

MRBLEs 2.0: High-throughput generation of chemically functionalized spectrally and magnetically-encoded hydrogel beads using a simple single-layer microfluidic device

Widespread adoption of bead-based multiplexed bioassays requires the ability to easily synthesize encoded microspheres and conjugate analytes of interest to their surface. Here, we present a simple method (MRBLEs 2.0) for efficient high-throughput generation of microspheres with ratiometric barcode lanthanide encoding (MRBLEs) bearing functional groups for downstream bioconjugation. Bead production in MRBLEs 2.0 relies on manual mixing of lanthanide/polymer mixtures (each of which comprises a unique spectral code) followed by droplet generation using single-layer, parallel flow-focusing devices and off-chip batch polymerization of droplets into beads. To streamline downstream analyte coupling, MRBLEs 2.0 crosslinks copolymers bearing functional groups on the bead surface simultaneously during bead generation. Using the MRBLEs 2.0 pipeline, we generate monodisperse MRBLEs containing 48 distinct well-resolved spectral codes in high-throughput (>150,000/min and can be boosted to 450,000/min). We further demonstrate the efficient conjugation of oligonucleotides and entire proteins to carboxyl MRBLEs and biotin to amino MRBLEs. Finally, we show that MRBLEs can also be magnetized via simultaneous incorporation of magnetic nanoparticles with only a minor decrease in the potential code space. We anticipate that MRBLEs 2.0 can be directly applied towards a wide variety of downstream assays from basic biology to diagnostics and other translational research.Competing Interest StatementStanford University and Chan Zuckerberg Biohub have filed a provisional patent application (U.S. Provisional Patent application No. 63/037,804) on the MRBLEs 2.0 methods described here and Y.F., A.K.W., J.B.H., and P.M.F. are named as inventors.View Full Text

bioengineering↗

bioRxiv2020

The minor and major spliceosome interact to regulate alternative splicing around minor introns

Mutations in minor spliceosome components are linked to diseases such as Roifman syndrome, Lowry-Wood syndrome, and early-onset cerebellar ataxia (EOCA). Here we report that besides increased minor intron retention, Roifman syndrome and EOCA can also be characterized by elevated alternative splicing (AS) around minor introns. Consistent with the idea that the assembly/activity of the minor spliceosome informs AS in minor intron-containing genes (MIGs), inhibition of all minor spliceosome snRNAs led to upregulated AS. Notably, alternatively spliced MIG isoforms were bound to polysomes in the U11-null dorsal telencephalon, which suggested that aberrant MIG protein expression could contribute to disease pathogenesis. In agreement, expression of an aberrant isoform of the MIG Dctn3 by in utero electroporation, affected radial glial cell divisions. Finally, we show that AS around minor introns is executed by the major spliceosome and is regulated by U11-59K of the minor spliceosome, which forms exon-bridging interactions with proteins of the major spliceosome. Overall, we extend the exon-definition model to MIGs and postulate that disruptions of exon-bridging interactions might contribute to disease severity and pathogenesis.

molecular biology↗