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- Bai, Bing, et al.
(författare)
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SeedTransNet : a directional translational network revealing regulatory patterns during seed maturation and germination
- 2023
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 74:7, s. 2416-2432
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Tidskriftsartikel (refereegranskat)abstract
- Seed maturation is the developmental process that prepares the embryo for the desiccated waiting period before germination. It is associated with a series of physiological changes leading to the establishment of seed dormancy, seed longevity, and desiccation tolerance. We studied translational changes during seed maturation and observed a gradual reduction in global translation during seed maturation. Transcriptome and translatome profiling revealed specific reduction in the translation of thousands of genes. By including previously published data on germination and seedling establishment, a regulatory network based on polysome occupancy data was constructed: SeedTransNet. Network analysis predicted translational regulatory pathways involving hundreds of genes with distinct functions. The network identified specific transcript sequence features suggesting separate translational regulatory circuits. The network revealed several seed maturation-associated genes as central nodes, and this was confirmed by specific seed phenotypes of the respective mutants. One of the regulators identified, an AWPM19 family protein, PM19-Like1 (PM19L1), was shown to regulate seed dormancy and longevity. This putative RNA-binding protein also affects the translational regulation of its target mRNA, as identified by SeedTransNet. Our data show the usefulness of SeedTransNet in identifying regulatory pathways during seed phase transitions.
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| 3. |
- Gestin, Maxime, et al.
(författare)
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Evaluation of the impact of length of peptide nucleic acid probes for tumor pretargeting
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Pretargeting is a strategy to improve the tumor-to-healthy tissue contrast in targeted nuclear imaging and therapy. The strategy relies on separating the tumor-targeting agent from the radioactive payload and combine the two in vivo. In the pretargeting approach previously studied by our group, the tumor targeting was mediated by an Affibody functionalized with a peptide nucleic acid (PNA) probe and the radionuclide was carried by a complementary PNA probe. Affibody-mediated PNA-based pretargeting was shown to increase the tumor-to-kidney ratio when evaluated in HER2-overexpressing tumor-bearing mice. The aim of the current study is to further optimize the design of the PNA probes to achieve better biodistribution properties and preconditions for a more cost-efficient production. The first important feature of the PNA pretargeting system is the tumor-to-kidney ratio, where the kidney retention is the dose-limiting factor for a clinical therapeutic application. The second aspect is the production of PNA, where the synthesis of PNA strands can be a challenge due to the steric repulsion between two PNA residues’ side chain and poor solubility in the synthesis solvent. In order to simplify the synthesis, we optimized the automation of the process using a microwave-assisted peptide synthesizer. Once the automated synthesis protocols were set up, we designed and synthesized a panel of new PNA probes, aimed at reducing the length of the PNA strands. The reduction in length was expected to simplify the synthesis workflow, but also to possibly decrease the kidney retention of the radioactive payload, as was shown in a previous study when reducing the length of the secondary PNA strand could improve the tumor-to-kidney ratio. The PNA duplexes were studied by CD and UV spectroscopy, and the binding kinetics of the interaction were studied by SPR to identify the limit in terms of number of base pairs needed to reach the high affinity expected to be required for an efficient pretargeting system. Our results showed that high affinity duplexes are formed between PNA probes having only 8 to 9 complementary bases, but that PNA probes with 6 or 7 complementary bases give rise to less stable duplexes having lower melting temperatures and faster dissociation rates.
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| 4. |
- Karlström, Jacob, et al.
(författare)
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SRIQ clustering : A fusion of Random Forest, QT clustering, and KNN concepts
- 2022
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Ingår i: Computational and Structural Biotechnology Journal. - : Elsevier BV. - 2001-0370. ; 20, s. 1567-1579
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Tidskriftsartikel (refereegranskat)abstract
- Gene expression profiling together with unsupervised analysis methods, typically clustering methods, has been used extensively in cancer research to unravel, e.g., new molecular subtypes that hold promise of disease refinement that may ultimately benefit patients. However, many of the commonly used methods require a prespecified number of clusters to extract and frequently require some type of feature pre-selection, e.g. variance filtering. This introduces subjectivity to the process of cluster discovery and the definition of putative novel tumor subtypes. Here, we introduce SRIQ, a novel unsupervised clustering method that could circumvent some of the issues in commonly used unsupervised analysis methods. SRIQ incorporates concepts from random forest machine learning as well as quality threshold- and k-nearest neighbor clustering. It is implemented as a Java and Python pipeline including data pre-processing, differential expression analysis, and pathway analysis. Using 434 lung adenocarcinomas profiled by RNA sequencing, we demonstrate the technical reproducibility of SRIQ and benchmark its performance compared to the commonly used consensus clustering method. Based on differential gene expression analysis and auxiliary molecular data we show that SRIQ can define new tumor subsets that appear biologically relevant and consistent compared and that these new subgroups seem to refine existing transcriptional subtypes that were defined using consensus clustering. Together, this provides support that SRIQ may be a useful new tool for unsupervised analysis of gene expression data from human malignancies.
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