Biology subjects

Oliver, D.

Publications and source records attributed to Oliver, D..

22 records · Page 2Linked to original sources

bioRxiv2020

A second PI(4,5)P2 binding site determines PI(4,5)P2 sensitivity of the tubby domain

Phosphosinositides (PIs) are lipid signaling molecules that operate by recruiting proteins to cellular membranes via PI recognition domains. Such domains are also used widely as fluorescence-coupled biosensors for cellular PIs. For PI(4,5)P2, the dominant PI of the plasma membrane (PM), only two recognition domains have been characterized in detail and used as sensors. One of them, the tubby domain, which is conserved in the tubby-like protein (TULP) family, is essential for targeting proteins into cilia in a process involving reversible membrane association. However, the PI(4,5)P2 binding properties of tubby domains have remained enigmatic. Here we used coarse-grained molecular dynamics (MD) simulations to explore PI(4,5)P2 binding by the prototypic tubby domain (tubbyCT). While the MD simulations showed a comparatively low PI(4,5)P2 affinity of the previously described canonical binding site, they unexpectedly revealed an adjacent second binding site, consisting of a conserved cationic cluster at the protein-membrane interface. Population of this second site dramatically increased membrane association of tubbyCT. Although less specific than the canonical binding pocket, this second site preferred binding of PI(4,5)P2 over PI(4)P and phosphatidyl serine. Mutations in this site impaired PI(4,5)P2-dependent PM localization in living cells and PI(4,5)P2 interaction in silico. Thus, the second binding site essentially contributes to the effective affinity and hence PM association of the tubby domain. The two-ligand binding mode may serve to sharpen the membrane association-dissociation cycle of TULPs that underlies delivery of ciliary cargo.

biophysics↗

bioRxiv2020

An integrated, modular approach to data science education in the life sciences

We live in an increasingly data-driven world, where high-throughput sequencing and mass spectrometry platforms are transforming biology into an information science. This has shifted major challenges in biological research from data generation and processing to interpretation and knowledge translation. However, post-secondary training in bioinformatics, or more generally data science for life scientists, lags behind current demand. In particular, development of accessible, undergraduate data science curricula has potential to improve research and learning outcomes and better prepare students in the life sciences to thrive in public and private sector careers. Here, we describe the Experiential Data science for Undergraduate Cross-Disciplinary Education (EDUCE) initiative, which aims to progressively build data science competency across several years of integrated practice. Through EDUCE, students complete data science modules integrated into required and elective courses augmented with coordinated co-curricular activities. The EDUCE initiative draws on a community of practice consisting of teaching assistants, postdocs, instructors and research faculty from multiple disciplines to overcome several reported barriers to data science for life scientists, including instructor capacity, student prior knowledge, and relevance to discipline-specific problems. Preliminary survey results indicate that even a single module improves student self-reported interest and/or experience in bioinformatics and computer science. Thus, EDUCE provides a flexible and extensible active learning framework for integration of data science curriculum into undergraduate courses and programs across the life sciences. Availability and implementationThe EDUCE teaching and learning framework is accessible at educe-ubc.github.io

scientific communication and education↗

bioRxiv2019

Precise removal of Calm1 long 3′ UTR isoform by CRISPR-Cas9 genome editing impairs dorsal root ganglion development in mice.

Most mammalian genes are subject to Alternative cleavage and PolyAdenylation (APA), often resulting in alternative length 3' UTR isoforms. Thousands of extended or long 3' UTR variants are preferentially expressed in neuron-enriched tissues of metazoans. However, the in vivo functions of these long 3' UTR isoforms are largely unknown. Calmodulin 1 (Calm1) is a key integrator of calcium signaling that is required for correct neural development. Calm1 generates short (Calm1-S) and long 3' UTR (Calm1-L) mRNA isoforms via APA. We found Calm1-S to be broadly expressed across mouse tissues, whereas Calm1-L expression was largely restricted to neural tissues, including the dorsal root ganglion (DRG). Using CRISPR-Cas9 genome editing, a series of mouse deletion lines were generated that successfully eliminated expression of Calm1-L while maintaining expression of Calm1-S. One of these lines, Calm1{Delta}3' UTR, carried a 163 bp deletion surrounding the distal polyA site. Examination of Calm1{Delta}3' UTR embryos revealed disrupted development of the DRG. In Calm1{Delta}3' UTR DRG explant cultures undergoing axon outgrowth, we observed a dramatic increase in axon fasciculation. These results demonstrate a physiological role for Calm1-L in DRG development, and more generally, establish a genome-editing strategy to study in vivo functions of long 3' UTR isoforms. Author SummaryMore than half of all human genes generate alternative mRNA isoforms which differ in the length of their 3 Untranslated regions (3 UTRs). Through a process called Alternative Cleavage and Polyadenylation thousands of broadly expressed genes preferentially express long 3 UTR variants in brain tissues whereas their short 3 UTR counterparts are more broadly expressed. A challenge to study the functions of these transcripts has been to generate loss of function mutant animals that lack a long 3 UTR isoform but maintain expression of the corresponding short 3 UTR isoform. Here, we used the precise, rapid, and efficient approach of CRISPR genome-editing to generate long 3 UTR mutant mice. These mice, which do not express the long 3 UTR of the Calmodulin 1 (Calm1) gene, exhibit impairment in the development of sensory neurons, including increased fasciculation of axons and aberrant cell body migration. This finding is important because it provides conclusive genetic evidence for a neural function of a long 3 UTR isoform in an animal. The CRISPR genome-editing approach used here can be applied to the study of neuron-enriched long 3 UTR isoforms, which number in the thousands and have largely unexplored functions.

genetics↗

bioRxiv2019

Structural basis for functional interactions in dimers of SLC26 transporters

The SLC26 family of transporters maintains anion equilibria in all kingdoms of life. The family shares a 7 + 7 transmembrane segments inverted repeat architecture with the SLC4 and SLC23 families, but holds a regulatory STAS domain in addition. While the only experimental SLC26 structure is monomeric, SLC26 proteins form structural and functional dimers in the lipid membrane. Here we resolve the structure of an SLC26 dimer embedded in a lipid membrane and characterize its functional relevance by combining PELDOR distance measurements and biochemical studies with MD simulations and spin-label ensemble refinement. Our structural model reveals a unique interface different from the SLC4 and SLC23 families. The functionally relevant STAS domain exerts a stabilizing effect on regions central in this dimer. Characterization of heterodimers indicates that protomers in the dimer functionally interact. The combined structural and functional data define the framework for a mechanistic understanding of functional cooperativity in SLC26 dimers.

biochemistry↗