Charles S Bond

University of Western Australia | UWA · School of Chemistry and Biochemistry

Restorer‐of‐fertility ( Rf ) genes encode pentatricopeptide repeat (PPR) proteins that are targeted to mitochondria where they specifically bind to transcripts that induce cytoplasmic male sterility and repress their expression. In searching for a molecular signature unique to this class of proteins, we found that a majority of known Rf proteins ha...

Horizontal gene transfer is tightly regulated in bacteria. Often only a fraction of cells become donors even when regulation of horizontal transfer is coordinated at the cell population level by quorum sensing. Here, we reveal the widespread 'domain of unknown function' DUF2285 represents an 'extended-turn' variant of the helix-turn-helix domain th...

Restorer-of-fertility (Rf) genes have practical applications in hybrid seed production as a means to control self-pollination. They encode pentatricopeptide repeat (PPR) proteins that are targeted to mitochondria where they specifically bind to transcripts that induce cytoplasmic male sterility and repress their expression. In searching for a molec...

Demixing of proteins and nucleic acids into condensed liquid phases is rapidly emerging as a ubiquitous mechanism governing the organisation of molecules within the cell. Long disordered low complexity regions (LCRs) are a common feature of proteins that form biomolecular condensates. RNA-binding proteins with prion-like composition have been highl...

High-risk neuroblastoma patients have poor survival rates and require better therapeutic options. High expression of a multifunctional DNA and RNA-binding protein, NONO, in neuroblastoma is associated with poor patient outcome; however, there is little understanding of the mechanism of NONO-dependent oncogenic gene regulatory activity in neuroblast...

RNA-binding proteins of the DBHS (Drosophila Behavior Human Splicing) family, NONO, SFPQ, and PSPC1 have numerous roles in genome stability and transcriptional and post-transcriptional regulation. Critical to DBHS activity is their recruitment to distinct subnuclear locations, for example paraspeckle condensates, where DBHS proteins bind to the lon...

The recombination directionality factors from Mesorhizobium spp. (RdfS) are involved in regulating the excision and transfer of integrative and conjugative elements. Here, solution small-angle X-ray scattering, and crystallization and preliminary structure solution of RdfS from Mesorhizobium japonicum R7A are presented. RdfS crystallizes in space g...

Decades of intense herbicide use has led to resistance in weeds. Without innovative weed management practices and new herbicidal modes of action, the unabated rise of herbicide resistance will undoubtedly place further stress upon food security. HMGR (3-hydroxy-3-methylglutaryl-coenzyme A reductase) is the rate limiting enzyme of the eukaryotic mev...

HMGR (3-hydroxy-3-methylglutaryl-coenzyme A reductase) is the rate limiting enzyme of the eukaryotic mevalonate pathway successfully targeted by statins to treat hypercholesterolemia in humans. The first statins to market have also been shown to be herbicidal yet their development as herbicides has been hindered by the risk of off-target effects. H...

Oligonucleotides and nucleic acid analogues that alter gene expression are now showing therapeutic promise in human disease. Whilst the modification of synthetic nucleic acids to protect against nuclease degradation and to influence drug function is common practice, such modifications may also confer unexpected physicochemical and biological proper...

Herbicides are vital for modern agriculture, but their utility is threatened by genetic or metabolic resistance in weeds as well as regulatory barriers. Of the known herbicide modes of action, 7,8-dihydropterin synthase (DHPS) which is involved in folate biosynthesis, is targeted by just one commercial herbicide, asulam. A mimic of the substrate pa...

High-risk neuroblastoma patients have poor survival rates and require better therapeutic options. High expression of a multifunctional DNA and RNA binding protein, NONO, in neuroblastoma is associated with poor patient outcome, however there is little understanding of the mechanism of NONO-dependent oncogenic gene regulatory activity in neuroblasto...

KARRIKIN INSENSITIVE2 (KAI2) is an α/β-hydrolase required for plant responses to karrikins, which are abiotic butenolides that can influence seed germination and seedling growth. Although represented by four angiosperm species, loss-of-function kai2 mutants are phenotypically inconsistent and incompletely characterised, resulting in uncertainties a...

Pentatricopeptide repeat (PPR) proteins are RNA-binding proteins that are attractive tools for RNA processing in synthetic biology applications given their modular structure and ease of design. Several distinct types of motifs have been described from natural PPR proteins, but almost all work so far with synthetic PPR proteins has focused on the mo...

Herbicides are vital for modern agriculture, but their utility is threatened by genetic or metabolic resistance in weeds as well as heightened regulatory scrutiny. Of the known herbicide modes of action, 6-hydroxymethyl-7,8-dihydropterin synthase (DHPS) which is involved in folate biosynthesis, is targeted by just one commercial herbicide, asulam....

Head-to-tail cyclic and disulfide-rich peptides are natural products with applications in drug design. Among these are the PawS-Derived Peptides (PDPs) produced in seeds of the daisy plant family. PDP-23 is a unique member of this class in that it is twice the typical size and adopts two β-hairpins separated by a hinge region. The β-hairpins, both...

Head-to-tail cyclic and disulfide-rich peptides are natural products with applications in drug design. Among these are the PawS-Derived Peptides (PDPs) produced in seeds of the daisy plant family. PDP-23 is a unique member of this class in that it is twice the typical size and adopts two β-hairpins separated by a hinge region. The β-hairpins - both...

Paraspeckles are RNA–protein structures within the nucleus of mammalian cells, capable of orchestrating various biochemical processes. An overexpression of the architectural component of paraspeckles, a long non-coding RNA called NEAT1 (Nuclear Enriched Abundant Transcript 1), has been linked to a variety of cancers and is often associated with poo...

Members of the pentatricopeptide repeat (PPR) protein family act as specificity factors in C-to-U RNA editing. The expansion of the PPR superfamily in plants provides the sequence variation required for design of consensus-based RNA-binding proteins. We used this approach to design a synthetic RNA editing factor to target one of the sites in the Ar...

Over 30 years ago, an intriguing post-translational modification was found responsible for creating concanavalin A (conA), a carbohydrate-binding protein from jack bean (Canavalia ensiformis) seeds and a common carbohydrate chromatography reagent. ConA biosynthesis involves what was then an unprecedented rearrangement in amino-acid sequence, whereb...

In Staphylococcus aureus, most multiresistance plasmids lack conjugation or mobilization genes for horizontal transfer. However, most are mobilizable due to carriage of origin-of-transfer (oriT) sequences mimicking those of conjugative plasmids related to pWBG749. pWBG749-family plasmids have diverged to carry five distinct oriT subtypes and non-co...

Targeted cytidine to uridine RNA editing is a widespread phenomenon throughout the land plant lineage. Members of the pentatricopeptide repeat (PPR) protein family act as the specificity factors in this process. These proteins consist of helix-turn-helix domains, each of which recognises a single RNA nucleotide following a well-elucidated code. A c...

Over 30 years ago, an intriguing post-translational modification was discovered to be responsible for creating concanavalin A (conA), a carbohydrate-binding protein found in the seeds of jack bean ( Canavalia ensiformis ) and commercially used for carbohydrate chromatography. Biosynthesis of conA involves what was then an unprecedented rearrangemen...

Human pancreatic islet amyloid polypeptide (hIAPP) and beta amyloid (Aβ) can accumulate in Type 2 diabetes (T2D) and Alzheimer’s disease (AD) brains and evidence suggests that interaction between the two amyloidogenic proteins can lead to the formation of heterocomplex aggregates. However, the structure and consequences of the formation of these co...

Aberrant KRAS signaling is a driver of many cancers and yet remains an elusive target for drug therapy. The nuclease hypersensitive element of the KRAS promoter has been reported to form secondary DNA structures called G-quadruplexes (G4s) which may play important roles in regulating KRAS expression, and has spurred interest in structural elucidati...

Wildfires can encourage the establishment of invasive plants by releasing potent germination stimulants, such as karrikins. Seed germination of Brassica tournefortii, a noxious weed of Mediterranean climates, is strongly stimulated by KAR1, the archetypal karrikin produced from burning vegetation. In contrast, the closely-related yet non-fire-assoc...

Scar formation after wound healing is a major medical problem. A better understanding of the dynamic nuclear architecture of the genome during wound healing could provide insights into the underlying pathophysiology and enable novel therapeutic strategies. Here, we demonstrate that TGF‐β‐ induced fibrotic stress increases formation of the dynamic s...

The RNA-binding pentatricopeptide repeat (PPR) family comprises hundreds to thousands of genes in most plants, but only a few dozen in algae, evidence of massive gene expansions during land plant evolution. The nature and timing of these expansions has not been well-defined due to the sparse sequence data available from early-diverging land plant l...

Horizontal transfer of plasmids encoding antimicrobial-resistance and virulence determinants has been instrumental in Staphylococcus aureus evolution, including the emergence of community-associated methicillin-resistant S. aureus (CA-MRSA). In the early 1990s the first CA-MRSA isolated in Western Australia (WA), WA-5, encoded cadmium, tetracycline...

Most structure‐based drug discovery protocols utilize crystal structures of receptor proteins. Crystal engineering, on the other hand, utilizes the wealth of chemical information inherent in small‐molecule crystal structures in the Cambridge Structural Database (CSD). Here we show that interaction surfaces and shapes of molecules in experimentally...

Most structure‐based drug discovery protocols utilize crystal structures of receptor proteins. Crystal engineering, on the other hand, utilizes the wealth of chemical information inherent in small‐molecule crystal structures in the Cambridge Structural Database (CSD). Here we show that interaction surfaces and shapes of molecules in experimentally...

Integrative and conjugative elements (ICEs) are chromosomally-integrated mobile genetic elements that excise from their host chromosome and transfer to other bacteria via conjugation. ICEMlSym R7A is the prototypical member of a large family of “symbiosis ICEs” which confer upon their hosts the ability to form a nitrogen-fixing symbiosis with a var...

Plant asparaginyl endopeptidases (AEPs) are expressed as inactive zymogens that perform seed storage protein maturation upon cleavage dependent auto‐activation in the low pH environment of storage vacuoles. AEPs have attracted attention for their macrocyclization reactions and have been classified as cleavage or ligation specialists. However, we ha...

Gold nanorods are one of the most widely explored inorganic materials in nanomedicine for diagnostics, therapeutics and sensing¹. It has been shown that gold nanorods are not cytotoxic and localize within cytoplasmic vesicles following endocytosis, with no nuclear localization2,3, but other studies have reported alterations in gene expression profi...

Detection of viruses by innate immune sensors induces protective antiviral immunity. The viral DNA sensor cyclic GMP-AMP synthase (cGAS) is necessary for detection of HIV by human dendritic cells and macrophages. However, synthesis of HIV DNA during infection is not sufficient for immune activation. The capsid protein, which associates with viral D...

Plant asparaginyl endopeptidases (AEPs) have attracted attention for their macrocyclization reactions and are usually classified as cleavage or ligation specialists. Like most proteases, AEPs are expressed as zymogens that self-cleave to become active. Recently, Haywood et al. (2018) showed several AEPs were capable of macrocyclization given favora...

A class of long noncoding RNAs (lncRNAs) has architectural functions in nuclear body construction; however, specific RNA domains dictating their architectural functions remain uninvestigated. Here, we identified the domains of the architectural NEAT1 lncRNA that construct paraspeckles. Systematic deletion of NEAT1 portions using CRISPR/Cas9 in hapl...

Members of the Drosophila Behavior Human Splicing (DBHS) protein family are nuclear proteins implicated in many layers of nuclear functions, including RNA biogenesis as well as DNA repair. Definitive of the DBHS protein family, the conserved DBHS domain provides a dimerization platform that is critical for the structural integrity and function of t...

ELife digest Most proteins are long, chain-like molecules that have two ends respectively called the N-terminus and C-terminus. However, certain proteins can close on themselves to become circular. This requires a chemical reaction between the N- and C-termini, which creates a strong bond between the two extremities. To go through this ‘cyclization...

Cytosolic thiolase (CT) catalyzes the reversible Claisen condensation of two molecules of acetyl-CoA to produce acetoacetyl-CoA. The reaction cycle proceeds via a ping-pong mechanism involving an acetylated enzyme intermediate and two separate oxyanion holes which stabilize negatively charged reaction intermediates. This is the initial step in the...

Long noncoding RNA (lncRNA) molecules are some of the newest and least understood players in gene regulation. Hence, we need good model systems with well-defined RNA and protein components. One such system is paraspeckles - protein-rich nuclear organelles built around a specific lncRNA scaffold. New discoveries show how paraspeckles are formed thro...

Movie S3. Motility and Morphology of 30 hpf sfpq−/− Embryos Rescued by Injection of Full-Length or ΔNLS Human sfpq RNA, Related to Figure 6

Movie S2. Video Showing Movement in 30 hpf sfpq−/− Embryos in Tg(Xla.Tubb2b:Hsa.MAPT-GFP)zc1 Background, Related to Figure 2

Movie S1. Video of 18–20 Somite Stage Embryos from a sfpq+/− Heterozygous Cross, Showing Spontaneous Movement in Siblings and No Movement at All in Homozygous Embryos from the Same Clutch, Related to Figure 1

Recent progress revealed the complexity of RNA processing and its association to human disorders. Here, we unveil a new facet of this complexity. Complete loss of function of the ubiquitous splicing factor SFPQ affects zebrafish motoneuron differentiation cell autonomously. In addition to its nuclear localization, the protein unexpectedly localizes...

Bowman-Birk Inhibitors (BBIs) are a well-known family of plant protease inhibitors first described 70 years ago. BBIs are known only in the legume (Fabaceae) and cereal (Poaceae) families, but peptides that mimic their trypsin inhibitory loops exist in sunflowers and frogs. The disparate biosynthetic origins and distant phylogenetic distribution im...

The methods of structural biology, while powerful, are technically complex. Although the Protein Data Bank (PDB) provides a repository that allows anyone to download any structure, many users would not appreciate the caveats that should be considered when examining a structure. Here, we describe several key uncertainties associated with the applica...

Paraspeckles are nuclear bodies built on the long noncoding RNA Neat1, which regulates a variety of physiological processes including cancer progression and corpus luteum formation. To obtain further insight into the molecular basis of the function of paraspeckles, we performed fine structural analyses of these nuclear bodies using structural illum...

Non-POU domain-containing octamer-binding protein (NONO, a.k.a. p54 nrb ) is a central player in nuclear gene regulation with rapidly emerging medical significance. NONO is a member of the highly conserved Drosophila behaviour/human splicing (DBHS) protein family, a dynamic family of obligatory dimeric nuclear regulatory mediators. However, work wi...

Emerging data suggest that the mechanisms by which RNA-binding proteins (RBPs) interact with RNA and the rules governing specificity might be substantially more complex than those underlying their DNA-binding counterparts. Even our knowledge of what constitutes the RNA-bound proteome is contentious; recent studies suggest that 10–30% of RBPs contai...

Nuclear proteins are often given a concise title that captures their function, such as ‘transcription factor,’ ‘polymerase’ or ‘nuclear-receptor.’ However, for members of the Drosophila behavior/human splicing (DBHS) protein family, no such clean-cut title exists. DBHS proteins are frequently identified engaging in almost every step of gene regulat...

The pentatricopeptide repeat (PPR) proteins form one of the largest protein families in land plants. They are characterised by tandem 30-40 amino acid motifs that form an extended binding surface capable of sequence-specific recognition of RNA strands. Almost all of them are post-translationally targeted to plastids and mitochondria where they play...

Members of the Drosophila behaviour/human splicing (DBHS) protein family have been characterised in the vertebrates Homo sapiens and Mus musculus, and the invertebrates Drosophila melanogaster and Chironomus tentans. Collectively, both vertebrate and invertebrate DBHS proteins function throughout gene regulation, largely but not always, within the...

Prion-like domains (PLDs) are low complexity sequences found in RNA binding proteins associated with the neurodegenerative disorder amyotrophic lateral sclerosis. Recently, PLDs have been implicated in mediating gene regulation via liquid-phase transitions that drive ribonucleoprotein granule assembly. In this paper, we report many PLDs in proteins...

The field of structural biology has the unique advantage of being able to provide a comprehensive picture of biological mechanisms at the molecular and atomic level. Long noncoding RNAs (lncRNAs) represent the new frontier in the molecular biology of complex organisms yet it remains the least characterised of all the classes of RNA. Thousands of ne...

Obligate parasitic plants in the Orobanchaceae germinate after sensing plant hormones, strigolactones, exuded from host roots. In Arabidopsis thaliana, the α/β-hydrolase D14 acts as a strigolactone receptor that controls shoot branching, whereas its ancestral paralog, KAI2, mediates karrikin-specific germination responses. We observed that KAI2, bu...

SFPQ, (a.k.a. PSF), is a human tumor suppressor protein that regulates many important functions in the cell nucleus including coordination of long non-coding RNA molecules into nuclear bodies. Here we describe the first crystal structures of Splicing Factor Proline and Glutamine Rich (SFPQ), revealing structural similarity to the related PSPC1/NONO...

RNA editing factors of the pentatricopeptide repeat (PPR) family show a very high degree of sequence specificity in the recognition of their target sites. A molecular basis for target recognition by editing factors has been proposed based on statistical correlations but has not been tested experimentally. To achieve this, we systematically mutated...