Chris Rodrigues is primarily interested in understanding how bacterial biology is orchestrated at a molecular level. His research is focused on gene discovery and function and how proteins come together in space and time to organize and regulate the biology of the bacterial cell.
He obtained his PhD from the University of Technology Sydney (UTS) in 2011. His PhD research contributed to a shift in our understanding of how bacteria establish the position of the division site. His PhD research has been highlighted in multiple review articles and recommended by the Faculty of 1000.
From 2011 to 2017, he was a postdoctoral research fellow at the Harvard Medical School (USA). There his research focused on how bacteria differentiate into spores. His primary research focused on an poorly-characterized, multi-protein complex that is required for spore development. This protein complex connects the two cells required to generate the spore and has been likened to a primordial umbilical cord. His work identified new components of this complex, as well as defined how the different components come together to build a fully functioning complex. He also demonstrated that this protein complex contains ring-like proteins similar to those found in the specialized secretion systems of Gram-negative bacteria.
Chris Rodrigues joined UTS in March 2017 and is currently developing his independent research that will focus on bacterial spore formation in model and pathogenic bacteria.
Can supervise: YES
My research focuses on understanding how bacteria develop into spores. Bacterial spores are the hardiest cell type on Earth and allow bacteria to persist in the environment when nutritional conditions are no longer favourable for growth. Spores are resistant to common sterilization methods that kill most bacteria and are inert to antibiotics. Importantly, the spores of pathogenic bacteria constitute a significant health threat in hospital settings and community health care centers, as they are often the source of new and recurring infections. A better understanding of the molecular underpinnings of how bacteria develop into spores can provide valuable insights into new strategies aimed at interfering with this process.
Areas of research interest:
· Morphogenesis of the spore envelope
· Structure and function of a putative specialized secretion system required for spore development
· Physiology of spore development
General Microbiology (Subject Coordinator for the Summer - Block Mode)
Hajduk, IV, Mann, R, Rodrigues, CDA & Harry, EJ 2019, 'The ParB homologs, Spo0J and Noc, together prevent premature midcell Z ring assembly when the early stages of replication are blocked in Bacillus subtilis.', Molecular microbiology.View/Download from: Publisher's site
Precise cell division in coordination with DNA replication and segregation is of utmost importance for all organisms. The earliest stage of cell division is the assembly of a division protein FtsZ into a ring, known as the Z ring, at midcell. What still eludes us, however, is how bacteria precisely position the Z ring at midcell. Work in B. subtilis over the last two decades has identified a link between the early stages of DNA replication and cell division. A recent model proposed that the progression of the early stages of DNA replication leads to an increased ability for the Z ring to form at midcell. This model arose through studies examining Z ring position in mutants blocked at different steps of the early stages of DNA replication. Here, we show that this model is unlikely to be correct and the mutants previously studied generate nucleoids with different capacity for blocking midcell Z ring assembly. Importantly, our data suggest that two proteins of the widespread ParB family, Noc and Spo0J are required to prevent Z ring assembly over the bacterial nucleoid and help fine tune the assembly of the Z ring at midcell during the cell cycle.
Morlot, C & Rodrigues, CDA 2018, 'The New Kid on the Block: A Specialized Secretion System during Bacterial Sporulation', TRENDS IN MICROBIOLOGY, vol. 26, no. 8, pp. 663-676.View/Download from: UTS OPUS or Publisher's site
Ramírez-Guadiana, FH, Rodrigues, CDA, Marquis, KA, Campo, N, Barajas-Ornelas, RDC, Brock, K, Marks, DS, Kruse, AC & Rudner, DZ 2018, 'Evidence that regulation of intramembrane proteolysis is mediated by substrate gating during sporulation in Bacillus subtilis.', PLoS genetics, vol. 14, no. 11.View/Download from: UTS OPUS or Publisher's site
During the morphological process of sporulation in Bacillus subtilis two adjacent daughter cells (called the mother cell and forespore) follow different programs of gene expression that are linked to each other by signal transduction pathways. At a late stage in development, a signaling pathway emanating from the forespore triggers the proteolytic activation of the mother cell transcription factor σK. Cleavage of pro-σK to its mature and active form is catalyzed by the intramembrane cleaving metalloprotease SpoIVFB (B), a Site-2 Protease (S2P) family member. B is held inactive by two mother-cell membrane proteins SpoIVFA (A) and BofA. Activation of pro-σK processing requires a site-1 signaling protease SpoIVB (IVB) that is secreted from the forespore into the space between the two cells. IVB cleaves the extracellular domain of A but how this cleavage activates intramembrane proteolysis has remained unclear. Structural studies of the Methanocaldococcus jannaschii S2P homolog identified closed (substrate-occluded) and open (substrate-accessible) conformations of the protease, but the biological relevance of these conformations has not been established. Here, using co-immunoprecipitation and fluorescence microscopy, we show that stable association between the membrane-embedded protease and its substrate requires IVB signaling. We further show that the cytoplasmic cystathionine-β-synthase (CBS) domain of the B protease is not critical for this interaction or for pro-σK processing, suggesting the IVB-dependent interaction site is in the membrane protease domain. Finally, we provide evidence that the B protease domain adopts both open and closed conformations in vivo. Collectively, our data support a substrate-gating model in which IVB-dependent cleavage of A on one side of the membrane triggers a conformational change in the membrane-embedded protease from a closed to an open state allowing pro-σK access to the caged interior of the protease.
Trouve, J, Mohamed, A, Leisico, F, Contreras-Martel, C, Liu, B, Mas, C, Rudner, DZ, Rodrigues, CDA & Morlot, C 2018, 'Structural characterization of the sporulation protein GerM from Bacillus subtilis.', Journal of structural biology, vol. 204, no. 3, pp. 481-490.View/Download from: UTS OPUS or Publisher's site
The Gram-positive bacterium Bacillus subtilis responds to starvation by entering a morphological differentiation process leading to the formation of a highly resistant spore. Early in the sporulation process, the cell asymmetrically divides into a large compartment (the mother cell) and a smaller one (the forespore), which will maturate into a resistant spore. Proper development of the forespore requires the assembly of a multiprotein complex called the SpoIIIA-SpoIIQ complex or "A-Q complex". This complex involves the forespore protein SpoIIQ and eight mother cell proteins (SpoIIIAA to SpoIIIAH), many of which share structural similarities with components of specialized secretion systems and flagella found in Gram-negative bacteria. The assembly of the A-Q complex across the two membranes that separate the mother cell and forespore was recently shown to require GerM. GerM is a lipoprotein composed of two GerMN domains, a family of domains with unknown function. Here, we report X-ray crystallographic structures of the first GerMN domain of GerM at 1.0 Å resolution, and of the soluble domain of GerM (the tandem of GerMN domains) at 2.1 Å resolution. These structures reveal that GerMN domains can adopt distinct conformations and that the core of these domains display structural similarities with ring-building motifs found in components of specialized secretion system and in SpoIIIA proteins. This work provides an additional piece towards the structural characterization of the A-Q complex.
Ramirez-Guadiana, FH, Meeske, AJ, Rodrigues, CDA, Barajas-Ornelas, RDC, Kruse, AC & Rudner, DZ 2017, 'A two-step transport pathway allows the mother cell to nurture the developing spore in Bacillus subtilis', PLOS GENETICS, vol. 13, no. 9.View/Download from: UTS OPUS or Publisher's site
Ramírez-Guadiana, FH, Meeske, AJ, Wang, X, Rodrigues, CDA & Rudner, DZ 2017, 'The Bacillus subtilis germinant receptor GerA triggers premature germination in response to morphological defects during sporulation.', Molecular Microbiology, vol. 105, no. 5, pp. 689-704.View/Download from: UTS OPUS or Publisher's site
During sporulation in Bacillus subtilis, germinant receptors assemble in the inner membrane of the developing spore. In response to specific nutrients, these receptors trigger germination and outgrowth. In a transposon-sequencing screen, we serendipitously discovered that loss of function mutations in the gerA receptor partially suppress the phenotypes of > 25 sporulation mutants. Most of these mutants have modest defects in the assembly of the spore protective layers that are exacerbated in the presence of a functional GerA receptor. Several lines of evidence indicate that these mutants inappropriately trigger the activation of GerA during sporulation resulting in premature germination. These findings led us to discover that up to 8% of wild-type sporulating cells trigger premature germination during differentiation in a GerA-dependent manner. This phenomenon was observed in domesticated and undomesticated wild-type strains sporulating in liquid and on solid media. Our data indicate that the GerA receptor is poised on a knife's edge during spore development. We propose that this sensitized state ensures a rapid response to nutrient availability and also elicits premature germination of spores with improperly assembled protective layers resulting in the elimination of even mildly defective individuals from the population.
Meeske, AJ, Rodrigues, CDA, Brady, J, Lim, HC, Bernhardt, TG & Rudner, DZ 2016, 'High-Throughput Genetic Screens Identify a Large and Diverse Collection of New Sporulation Genes in Bacillus subtilis', PLOS BIOLOGY, vol. 14, no. 1.View/Download from: UTS OPUS or Publisher's site
Rodrigues, CD, Ramírez-Guadiana, FH, Meeske, AJ, Wang, X & Rudner, DZ 2016, 'GerM is required to assemble the basal platform of the SpoIIIA-SpoIIQ transenvelope complex during sporulation in Bacillus subtilis.', Molecular microbiology, vol. 102, no. 2, pp. 260-273.View/Download from: Publisher's site
Sporulating Bacillus subtilis cells assemble a multimeric membrane complex connecting the mother cell and developing spore that is required to maintain forespore differentiation. An early step in the assembly of this transenvelope complex (called the A-Q complex) is an interaction between the extracellular domains of the forespore membrane protein SpoIIQ and the mother cell membrane protein SpoIIIAH. This interaction provides a platform onto which the remaining components of the complex assemble and also functions as an anchor for cell-cell signaling and morphogenetic proteins involved in spore development. SpoIIQ is required to recruit SpoIIIAH to the sporulation septum on the mother-cell side, however the mechanism by which SpoIIQ specifically localizes to the septal membranes on the forespore side has remained enigmatic. Here, we identify GerM, a lipoprotein previously implicated in spore germination, as the missing factor required for SpoIIQ localization. Our data indicate that GerM and SpoIIIAH, derived from the mother cell, and SpoIIQ, from the forespore, have reciprocal localization dependencies suggesting they constitute a tripartite platform for the assembly of the A-Q complex and a hub for the localization of mother cell and forespore proteins. This article is protected by copyright. All rights reserved.
Rodrigues, CDA, Henry, X, Neumann, E, Kurauskas, V, Bellard, L, Fichou, Y, Schanda, P, Schoehn, G, Rudner, DZ & Morlot, C 2016, 'A ring-shaped conduit connects the mother cell and forespore during sporulation in Bacillus subtilis', PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, vol. 113, no. 41, pp. 11585-11590.View/Download from: UTS OPUS or Publisher's site
Widderich, N, Rodrigues, CDA, Commichau, FM, Fischer, KE, Ramirez-Guadiana, FH, Rudner, DZ & Bremer, E 2016, 'Salt-sensitivity of sigma(H) and Spo0A prevents sporulation of Bacillus subtilis at high osmolarity avoiding death during cellular differentiation', MOLECULAR MICROBIOLOGY, vol. 100, no. 1, pp. 108-124.View/Download from: Publisher's site
Hajduk, IV, Rodrigues, CD & Harry, EJ 2016, 'Connecting the dots of the bacterial cell cycle: Coordinating chromosome replication and segregation with cell division.', Seminars in cell & developmental biology, vol. 53, pp. 2-9.View/Download from: UTS OPUS or Publisher's site
Proper division site selection is crucial for the survival of all organisms. What still eludes us is how bacteria position their division site with high precision, and in tight coordination with chromosome replication and segregation. Until recently, the general belief, at least in the model organisms Bacillus subtilis and Escherichia coli, was that spatial regulation of division comes about by the combined negative regulatory mechanisms of the Min system and nucleoid occlusion. However, as we review here, these two systems cannot be solely responsible for division site selection and we highlight additional regulatory mechanisms that are at play. In this review, we put forward evidence of how chromosome replication and segregation may have direct links with cell division in these bacteria and the benefit of recent advances in chromosome conformation capture techniques in providing important information about how these three processes mechanistically work together to achieve accurate generation of progenitor cells.
Arrieta-Ortiz, ML, Hafemeister, C, Bate, AR, Chu, T, Greenfield, A, Shuster, B, Barry, SN, Gallitto, M, Liu, B, Kacmarczyk, T, Santoriello, F, Chen, J, Rodrigues, CD, Sato, T, Rudner, DZ, Driks, A, Bonneau, R & Eichenberger, P 2015, 'An experimentally supported model of the Bacillus subtilis global transcriptional regulatory network.', Molecular Systems Biology, vol. 11, no. 11, pp. 1-17.View/Download from: UTS OPUS or Publisher's site
Organisms from all domains of life use gene regulation networks to control cell growth, identity, function, and responses to environmental challenges. Although accurate global regulatory models would provide critical evolutionary and functional insights, they remain incomplete, even for the best studied organisms. Efforts to build comprehensive networks are confounded by challenges including network scale, degree of connectivity, complexity of organism-environment interactions, and difficulty of estimating the activity of regulatory factors. Taking advantage of the large number of known regulatory interactions in Bacillus subtilis and two transcriptomics datasets (including one with 38 separate experiments collected specifically for this study), we use a new combination of network component analysis and model selection to simultaneously estimate transcription factor activities and learn a substantially expanded transcriptional regulatory network for this bacterium. In total, we predict 2,258 novel regulatory interactions and recall 74% of the previously known interactions. We obtained experimental support for 391 (out of 635 evaluated) novel regulatory edges (62% accuracy), thus significantly increasing our understanding of various cell processes, such as spore formation.
Mastny, M, Heuck, A, Kurzbauer, R, Heiduk, A, Boisguerin, P, Volkmer, R, Ehrmann, M, Rodrigues, CDA, Rudner, DZ & Clausen, T 2013, 'CtpB Assembles a Gated Protease Tunnel Regulating Cell-Cell Signaling during Spore Formation in Bacillus subtilis', CELL, vol. 155, no. 3, pp. 647-658.View/Download from: UTS OPUS or Publisher's site
Rodrigues, CDA, Marquis, KA, Meisner, J & Rudner, DZ 2013, 'Peptidoglycan hydrolysis is required for assembly and activity of the transenvelope secretion complex during sporulation in Bacillus subtilis', MOLECULAR MICROBIOLOGY, vol. 89, no. 6, pp. 1039-1052.View/Download from: UTS OPUS or Publisher's site
Rodrigues, CD & Harry, L 2012, 'The Min System And Nucleoid Occlusion Are Not Required For Identifying The Division Site In Bacillus Subtilis But Ensure Its Efficient Utilization', PLoS Genetics, vol. 8, no. 3, pp. 1-20.View/Download from: UTS OPUS or Publisher's site
Precise temporal and spatial control of cell division is essential for progeny survival. The current general view is that precise positioning of the division site at midcell in rod-shaped bacteria is a result of the combined action of the Min system and
Moriya, S, Rashid, RA, Rodrigues, CD & Harry, L 2010, 'Influence of the nucleoid and the early stages of DNA replication on positioning the division site in Bacillus subtilis', Molecular Microbiology, vol. 76, no. 3, pp. 634-647.View/Download from: UTS OPUS or Publisher's site
Although division site positioning in rod~shaped bac~ teria is generally believed to occur through the com~ bined effect of nucleoid occlusion and the Min system, several lines of evidence suggest the existence of additional mechanisms. Studies using outgrown spores of Bacillus subtilis have shown that inhi·biting ~ the early stages of DNA replication, leading up to . assembly of the replisome at orie, influences Z ring positioning. Here we examine whether Z ring formation at midcell under various conditions of DNA replication inhibition is solely the result of relief of nucleoid occlusion. We show that midcell Z rings form preferentially over unreplicated nucleoids that have a bilobed mor~ phology (lowering DNA concentration at midcell), whereas acentral Z rings form beside a single~lobed nucleoid. Remarkably however, when the Dna8 repli~ cation initiation protein is inactivated midcell Z rings never form over bilobed nucleoids. Relieving nucleoid occlusion by deleting noc increased midcell Z ring frequency for all situations of DNA replication inhibItion, however not to the same extent, with the DnaB~ inactivated strain having the lowest frequency of midcell Z rings. We propose an additional mechanism for Z ring positioning in which the division site becomes increasingly potentiated for Z ring formation as initiation of replication is progressively completed.
Braun, M, Rodrigues, CD, Rudner, D & Karatekin, E 2015, 'Role of FisB-Cardiolipin Interactions in Membrane Fission during Sporulation in Bacillus Subtilis', BIOPHYSICAL JOURNAL, 59th Annual Meeting of the Biophysical-Society, CELL PRESS, Baltimore, MD, pp. 382A-382A.View/Download from: Publisher's site
Braun, M, Rodrigues, CD, Doan, T, Coleman, J, Rudner, D & Karatekin, E 2014, 'FisB Mediated Membrane Fission During Sporulation in Bacillus Subtilis', BIOPHYSICAL JOURNAL, 58th Annual Meeting of the Biophysical-Society, CELL PRESS, San Francisco, CA, pp. 524A-524A.View/Download from: Publisher's site