@article {126, title = {Profiling subcellular localization of nuclear-encoded mitochondrial gene products in zebrafish.}, journal = {Life Sci Alliance}, volume = {6}, year = {2023}, month = {2023 Jan}, abstract = {

Most mitochondrial proteins are encoded by nuclear genes, synthetized in the cytosol and targeted into the organelle. To characterize the spatial organization of mitochondrial gene products in zebrafish (), we sequenced RNA from different cellular fractions. Our results confirmed the presence of nuclear-encoded mRNAs in the mitochondrial fraction, which in unperturbed conditions, are mainly transcripts encoding large proteins with specific properties, like transmembrane domains. To further explore the principles of mitochondrial protein compartmentalization in zebrafish, we quantified the transcriptomic changes for each subcellular fraction triggered by the mutation, causing the disorders in the mitochondrial protein import. Our results indicate that the proteostatic stress further restricts the population of transcripts on the mitochondrial surface, allowing only the largest and the most evolutionary conserved proteins to be synthetized there. We also show that many nuclear-encoded mitochondrial transcripts translated by the cytosolic ribosomes stay resistant to the global translation shutdown. Thus, vertebrates, in contrast to yeast, are not likely to use localized translation to facilitate synthesis of mitochondrial proteins under proteostatic stress conditions.

}, keywords = {Animals, Genes, Mitochondrial, Mitochondria, Mitochondrial Proteins, Nuclear Proteins, RNA, Messenger, Saccharomyces cerevisiae, Zebrafish}, issn = {2575-1077}, doi = {10.26508/lsa.202201514}, author = {Uszczynska-Ratajczak, Barbara and Sugunan, Sreedevi and Kwiatkowska, Monika and Migdal, Maciej and Carbonell-Sala, Silvia and Sokol, Anna and Winata, Cecilia L and Chacinska, Agnieszka} } @article {127, title = {xcore: an R package for inference of gene expression regulators.}, journal = {BMC Bioinformatics}, volume = {24}, year = {2023}, month = {2023 Jan 11}, pages = {14}, abstract = {

BACKGROUND: Elucidating the Transcription Factors (TFs) that drive the gene expression changes in a given experiment is a common question asked by researchers. The existing methods rely on the predicted Transcription Factor Binding Site (TFBS) to model the changes in the motif activity. Such methods only work for TFs that have a motif and assume the TF binding profile is the same in all cell types.

RESULTS: Given the wealth of the ChIP-seq data available for a wide range of the TFs in various cell types, we propose that gene expression modeling can be done using ChIP-seq "signatures" directly, effectively skipping the motif finding and TFBS prediction steps. We present xcore, an R package that allows TF activity modeling based on ChIP-seq signatures and the user{\textquoteright}s gene expression data. We also provide xcoredata a companion data package that provides a collection of preprocessed ChIP-seq signatures. We demonstrate that xcore leads to biologically relevant predictions using transforming growth factor beta induced epithelial-mesenchymal transition time-courses, rinderpest infection time-courses, and embryonic stem cells differentiated to cardiomyocytes time-course profiled with Cap Analysis Gene Expression.

CONCLUSIONS: xcore provides a simple analytical framework for gene expression modeling using linear models that can be easily incorporated into differential expression analysis pipelines. Taking advantage of public ChIP-seq databases, xcore can identify meaningful molecular signatures and relevant ChIP-seq experiments.

}, keywords = {Animals, Binding Sites, Chromatin Immunoprecipitation, Chromatin Immunoprecipitation Sequencing, Gene Expression, Protein Binding, Transcription Factors}, issn = {1471-2105}, doi = {10.1186/s12859-022-05084-0}, author = {Migda{\l}, Maciej and Arakawa, Takahiro and Takizawa, Satoshi and Furuno, Masaaki and Suzuki, Harukazu and Arner, Erik and Winata, Cecilia Lanny and Kaczkowski, Bogumi{\l}} } @article {124, title = {Adar-mediated A-to-I editing is required for embryonic patterning and innate immune response regulation in zebrafish.}, journal = {Nat Commun}, volume = {13}, year = {2022}, month = {2022 Sep 20}, pages = {5520}, abstract = {

Adenosine deaminases (ADARs) catalyze the deamination of adenosine to inosine, also known as A-to-I editing, in RNA. Although A-to-I editing occurs widely across animals and is well studied, new biological roles are still being discovered. Here, we study the role of A-to-I editing in early zebrafish development. We demonstrate that Adar, the zebrafish orthologue of mammalian ADAR1, is essential for establishing the antero-posterior and dorso-ventral axes and patterning. Genome-wide editing discovery reveals pervasive editing in maternal and the earliest zygotic transcripts, the majority of which occurred in the 3{\textquoteright}-UTR. Interestingly, transcripts implicated in gastrulation as well as dorso-ventral and antero-posterior patterning are found to contain multiple editing sites. Adar knockdown or overexpression affect gene expression by 12 hpf. Analysis of adar-/- zygotic mutants further reveals that the previously described role of Adar in mammals in regulating the innate immune response is conserved in zebrafish. Our study therefore establishes distinct maternal and zygotic functions of RNA editing by Adar in embryonic patterning along the zebrafish antero-posterior and dorso-ventral axes, and in the regulation of the\ innate immune response, respectively.

}, keywords = {Adenosine, Animals, Immunity, Innate, Inosine, Mammals, RNA, RNA-Binding Proteins, Zebrafish}, issn = {2041-1723}, doi = {10.1038/s41467-022-33260-6}, author = {Niescierowicz, Katarzyna and Pryszcz, Leszek and Navarrete, Cristina and Tralle, Eugeniusz and Sulej, Agata and Abu Nahia, Karim and Kasprzyk, Marta El{\.z}bieta and Misztal, Katarzyna and Pateria, Abhishek and Paku{\l}a, Adrianna and Bochtler, Matthias and Winata, Cecilia} } @article {125, title = {Multiomic atlas with functional stratification and developmental dynamics of zebrafish cis-regulatory elements.}, journal = {Nat Genet}, volume = {54}, year = {2022}, month = {2022 Jul}, pages = {1037-1050}, abstract = {

Zebrafish, a popular organism for studying embryonic development and for modeling human diseases, has so far lacked a systematic functional annotation program akin to those in other animal models. To address this, we formed the international DANIO-CODE consortium and created a central repository to store and process zebrafish developmental functional genomic data. Our data coordination center ( https://danio-code.zfin.org ) combines a total of 1,802 sets of unpublished and re-analyzed published genomic data, which we used to improve existing annotations and show its utility in experimental design. We identified over 140,000 cis-regulatory elements throughout development, including classes with distinct features dependent on their activity in time and space. We delineated the distinct distance topology and chromatin features between regulatory elements active during zygotic genome activation and those active during organogenesis. Finally, we matched regulatory elements and epigenomic landscapes between zebrafish and mouse and predicted functional relationships between them beyond sequence similarity, thus extending the utility of zebrafish developmental genomics to mammals.

}, keywords = {Animals, Chromatin, Databases, Genetic, Gene Expression Regulation, Developmental, Genome, Genomics, Humans, Mice, Molecular Sequence Annotation, Organogenesis, Regulatory Sequences, Nucleic Acid, Zebrafish, Zebrafish Proteins}, issn = {1546-1718}, doi = {10.1038/s41588-022-01089-w}, author = {Baranasic, Damir and H{\"o}rtenhuber, Matthias and Balwierz, Piotr J and Zehnder, Tobias and Mukarram, Abdul Kadir and Nepal, Chirag and V{\'a}rnai, Csilla and Hadzhiev, Yavor and Jimenez-Gonzalez, Ada and Li, Nan and Wragg, Joseph and D{\textquoteright}Orazio, Fabio M and Relic, Dorde and Pachkov, Mikhail and D{\'\i}az, Noelia and Hern{\'a}ndez-Rodr{\'\i}guez, Benjam{\'\i}n and Chen, Zelin and Stoiber, Marcus and Dong, Micha{\"e}l and Stevens, Irene and Ross, Samuel E and Eagle, Anne and Martin, Ryan and Obasaju, Oluwapelumi and Rastegar, Sepand and McGarvey, Alison C and Kopp, Wolfgang and Chambers, Emily and Wang, Dennis and Kim, Hyejeong R and Acemel, Rafael D and Naranjo, Silvia and {\L}api{\'n}ski, Maciej and Chong, Vanessa and Mathavan, Sinnakaruppan and Peers, Bernard and Sauka-Spengler, Tatjana and Vingron, Martin and Carninci, Piero and Ohler, Uwe and Lacadie, Scott Allen and Burgess, Shawn M and Winata, Cecilia and van Eeden, Freek and Vaquerizas, Juan M and G{\'o}mez-Skarmeta, Jos{\'e} Luis and Onichtchouk, Daria and Brown, Ben James and Bogdanovic, Ozren and van Nimwegen, Erik and Westerfield, Monte and Wardle, Fiona C and Daub, Carsten O and Lenhard, Boris and M{\"u}ller, Ferenc} } @article {119, title = {Cardiac-specific β-catenin deletion dysregulates energetic metabolism and mitochondrial function in perinatal cardiomyocytes.}, journal = {Mitochondrion}, volume = {60}, year = {2021}, month = {2021 09}, pages = {59-69}, abstract = {

β-Catenin signaling pathway regulates cardiomyocytes proliferation and differentiation, though its involvement in metabolic regulation of cardiomyocytes remains unknown. We used one-day-old mice with cardiac-specific knockout of β-catenin and neonatal rat ventricular myocytes treated with β-catenin inhibitor to investigate the role of β-catenin metabolism regulation in perinatal cardiomyocytes. Transcriptomics of perinatal β-catenin-ablated hearts revealed a dramatic shift in the expression of genes involved in metabolic processes. Further analysis indicated an inhibition of lipolysis and glycolysis in both in vitro and in vivo models. Finally, we showed that β-catenin deficiency leads to mitochondria dysfunction via the downregulation of Sirt1/PGC-1α pathway. We conclude that cardiac-specific β-catenin ablation disrupts the energy substrate shift that is essential for postnatal heart maturation, leading to perinatal lethality of homozygous β-catenin knockout mice.

}, issn = {1872-8278}, doi = {10.1016/j.mito.2021.07.005}, author = {Balatskyi, Volodymyr V and Vaskivskyi, Vasyl O and Myronova, Anna and Avramets, Diana and Nahia, Karim Abu and Macewicz, Larysa L and Ruban, Tetiana P and Kucherenko, Dar{\textquoteright}ya Yu and Soldatkin, Oleksandr O and Lushnikova, Iryna V and Skibo, Galyna G and Winata, Cecilia L and Dobrzyn, Pawel and Piven, Oksana O} } @article {117, title = {Exploring Translational Control of Maternal mRNAs in Zebrafish.}, journal = {Methods Mol Biol}, volume = {2218}, year = {2021}, month = {2021}, pages = {367-380}, abstract = {

The study of translational regulation requires reliable measurement of both mRNA levels and protein synthesis. Cytoplasmic polyadenylation is a prevalent mode of translational regulation during oogenesis and early embryogenesis. Here the length of the poly(A) tail of an mRNA is coupled to its translatability. We describe a protocol to identify translationally regulated genes and measure their translation rate in the early zebrafish embryo using genome-wide polysome profiling. This protocol relies on the isolation of mRNA by means of an rRNA depletion strategy, which avoids capture bias due to short poly(A) tail that can occur when using conventional oligo(dT)-based methods. We also present a simple PCR-based method to measure the poly(A) tail length of selected mRNAs.

}, keywords = {Animals, Cytoplasm, Embryo, Nonmammalian, Embryonic Development, Oocytes, Oogenesis, Poly A, Polyadenylation, Protein Biosynthesis, RNA, Messenger, Stored, Zebrafish}, issn = {1940-6029}, doi = {10.1007/978-1-0716-0970-5_29}, author = {Winata, Cecilia Lanny and {\L}api{\'n}ski, Maciej and Ismail, Hisyam and Mathavan, Sinnakaruppan and Sampath, Prabha} } @article {120, title = {Genomic and physiological analyses of the zebrafish atrioventricular canal reveal molecular building blocks of the secondary pacemaker region.}, journal = {Cell Mol Life Sci}, volume = {78}, year = {2021}, month = {2021 Oct}, pages = {6669-6687}, abstract = {

The atrioventricular canal (AVC) is the site where key structures responsible for functional division between heart regions are established, most importantly, the atrioventricular (AV) conduction system and cardiac valves. To elucidate the mechanism underlying AVC development and function, we utilized transgenic zebrafish line sqet31Et expressing EGFP in the AVC to isolate this cell population and profile its transcriptome at 48 and 72 hpf. The zebrafish AVC transcriptome exhibits hallmarks of mammalian AV node, including the expression of genes implicated in its development and those encoding connexins forming low conductance gap junctions. Transcriptome analysis uncovered protein-coding and noncoding transcripts enriched in AVC, which have not been previously associated with this structure, as well as dynamic expression of epithelial-to-mesenchymal transition markers and components of TGF-β, Notch, and Wnt signaling pathways likely reflecting ongoing AVC and valve development. Using transgenic line Tg(myl7:mermaid) encoding voltage-sensitive fluorescent protein, we show that abolishing the pacemaker-containing sinoatrial ring (SAR) through Isl1 loss of function resulted in spontaneous activation in the AVC region, suggesting that it possesses inherent automaticity although insufficient to replace the SAR. The SAR and AVC transcriptomes express partially overlapping species of ion channels and gap junction proteins, reflecting their distinct roles. Besides identifying conserved aspects between zebrafish and mammalian conduction systems, our results established molecular hallmarks of the developing AVC which underlies its role in structural and electrophysiological separation between heart chambers. This data constitutes a valuable resource for studying AVC development and function, and identification of novel candidate genes implicated in these processes.

}, keywords = {Animals, Animals, Genetically Modified, Embryo, Nonmammalian, Gene Expression Regulation, Developmental, Genome, Genomics, Heart Septal Defects, Heart Valves, Myocardium, Organogenesis, Pacemaker, Artificial, Wnt Signaling Pathway, Zebrafish, Zebrafish Proteins}, issn = {1420-9071}, doi = {10.1007/s00018-021-03939-y}, author = {Abu Nahia, Karim and Migda{\l}, Maciej and Quinn, T Alexander and Poon, Kar-Lai and {\L}api{\'n}ski, Maciej and Sulej, Agata and Liu, Jiandong and Mondal, Shamba S and Pawlak, Micha{\l} and Bugajski, {\L}ukasz and Piwocka, Katarzyna and Brand, Thomas and Kohl, Peter and Korzh, Vladimir and Winata, Cecilia} } @article {121, title = {Transcriptome profile of the sinoatrial ring reveals conserved and novel genetic programs of the zebrafish pacemaker.}, journal = {BMC Genomics}, volume = {22}, year = {2021}, month = {2021 Oct 02}, pages = {715}, abstract = {

BACKGROUND: Sinoatrial Node (SAN) is part of the cardiac conduction system, which controls the rhythmic contraction of the vertebrate heart. The SAN consists of a specialized pacemaker cell population that has the potential to generate electrical impulses. Although the SAN pacemaker has been extensively studied in mammalian and teleost models, including the zebrafish, their molecular nature remains inadequately comprehended.

RESULTS: To characterize the molecular profile of the zebrafish sinoatrial ring (SAR) and elucidate the mechanism of pacemaker function, we utilized the transgenic line sqet33mi59BEt to isolate cells of the SAR of developing zebrafish embryos and profiled their transcriptome. Our analyses identified novel candidate genes and well-known conserved signaling pathways involved in pacemaker development. We show that, compared to the rest of the heart, the zebrafish SAR overexpresses several mammalian SAN pacemaker signature genes, which include hcn4 as well as those encoding calcium- and potassium-gated channels. Moreover, genes encoding components of the BMP and Wnt signaling pathways, as well as members of the Tbx family, which have previously been implicated in pacemaker development, were also overexpressed in the SAR. Among SAR-overexpressed genes, 24 had human homologues implicated in 104 different ClinVar phenotype entries related to various forms of congenital heart diseases, which suggest the relevance of our transcriptomics resource to studying human heart conditions. Finally, functional analyses of three SAR-overexpressed genes, pard6a, prom2, and atp1a1a.2, uncovered their novel role in heart development and physiology.

CONCLUSION: Our results established conserved aspects between zebrafish and mammalian pacemaker function and revealed novel factors implicated in maintaining cardiac rhythm. The transcriptome data generated in this study represents a unique and valuable resource for the study of pacemaker function and associated heart diseases.

}, keywords = {Animals, Heart Rate, Humans, Sinoatrial Node, Transcriptome, Zebrafish}, issn = {1471-2164}, doi = {10.1186/s12864-021-08016-z}, author = {Minhas, Rashid and Loeffler-Wirth, Henry and Siddiqui, Yusra H and Obr{\k e}bski, Tomasz and Vashisht, Shikha and Nahia, Karim Abu and Paterek, Alexandra and Brzozowska, Angelika and Bugajski, Lukasz and Piwocka, Katarzyna and Korzh, Vladimir and Binder, Hans and Winata, Cecilia Lanny} } @article {115, title = {Targeted RNA Knockdown by a Type III CRISPR-Cas Complex in Zebrafish.}, journal = {CRISPR J}, volume = {3}, year = {2020}, month = {2020 08}, pages = {299-313}, abstract = {

RNA interference is a powerful experimental tool for RNA knockdown, but not all organisms are amenable. Here, we provide a proof of principle demonstration that a type III Csm effector complex can be used for programmable mRNA transcript degradation in eukaryotes. In zebrafish, Csm complex (StCsm) proved effective for knockdown of maternally expressed in germ cells of fish. It also led to significant, albeit less drastic, fluorescence reduction at one day postfertilization in and ( fish that express zygotically. StCsm targeted against the endogenous elicited the characteristic one-eyed phenotype with greater than 50\% penetrance, and hence with similar efficiency to morpholino-mediated knockdown. We conclude that Csm-mediated knockdown is very efficient for maternal transcripts and can also be used for mixed maternal/early zygotic and early zygotic transcripts, in some cases reaching comparable efficiency to morpholino-based knockdown without significant off-target effects.

}, issn = {2573-1602}, doi = {10.1089/crispr.2020.0032}, author = {Fricke, Thomas and Smalakyte, Dalia and Lapinski, Maciej and Pateria, Abhishek and Weige, Charles and Pastor, Michal and Kolano, Agnieszka and Winata, Cecilia and Siksnys, Virginijus and Tamulaitis, Gintautas and Bochtler, Matthias} } @article {pmid29229769, title = {Cytoplasmic polyadenylation-mediated translational control of maternal mRNAs directs maternal-to-zygotic transition}, journal = {Development}, volume = {145}, year = {2018}, month = {01/2018}, abstract = {

In the earliest stages of animal development following fertilization, maternally deposited mRNAs direct biological processes to the point of zygotic genome activation (ZGA). These maternal mRNAs undergo cytoplasmic polyadenylation (CPA), suggesting translational control of their activation. To elucidate the biological role of CPA during embryogenesis, we performed genome-wide polysome profiling at several stages of zebrafish development. Our analysis revealed a correlation between CPA and polysome-association dynamics, demonstrating a coupling of translation to the CPA of maternal mRNAs. Pan-embryonic CPA inhibition disrupted the maternal-to-zygotic transition (MZT), causing a failure of developmental progression beyond the mid-blastula transition and changes in global gene expression that indicated a failure of ZGA and maternal mRNA clearance. Among the genes that were differentially expressed were those encoding chromatin modifiers and key transcription factors involved in ZGA, including nanog, pou5f3 and sox19b, which have distinct CPA dynamics. Our results establish the necessity of CPA for ensuring progression of the MZT. The RNA-seq data generated in this study represent a valuable zebrafish resource for the discovery of novel elements of the early embryonic transcriptome.

}, author = {Winata, C. L. and {\L}api{\'n}ski, M. and Pryszcz, L. and Vaz, C. and Bin Ismail, M. H. and Nama, S. and Hajan, H. S. and Lee, S. G. P. and Korzh, V. and Sampath, P. and Tanavde, V. and Mathavan, S.} } @article {74, title = {Impaired development of neural-crest cell-derived organs and intellectual disability caused by MED13L haploinsufficiency.}, journal = {Hum Mutat}, volume = {35}, year = {2014}, month = {2014 Nov}, pages = {1311-20}, abstract = {

MED13L is a component subunit of the Mediator complex, an important regulator of transcription that is highly conserved across eukaryotes. Here, we report MED13L disruption in a translocation t(12;19) breakpoint of a patient with Pierre-Robin syndrome, moderate intellectual disability, craniofacial anomalies, and muscular defects. The phenotype is similar to previously described patients with MED13L haploinsufficiency. Knockdown of MED13L orthologue in zebrafish, med13b, showed early defective migration of cranial neural crest cells (NCCs) that contributed to cartilage structure deformities in the later stage, recapitulating craniofacial anomalies seen in human patients. Notably, we observed abnormal distribution of developing neurons in different brain regions of med13b morphant embryos, which could be rescued upon introduction of full-length human MED13L mRNA. To compare with mammalian system, we suppressed MED13L expression by short-hairpin RNA in ES-derived human neural progenitors, and differentiated them into neurons. Transcriptome analysis revealed differential expression of components of Wnt and FGF signaling pathways in MED13L-deficient neurons. Our finding provides a novel insight into the mechanism of overlapping phenotypic outcome targeting NCCs derivatives organs in patients with MED13L haploinsufficiency, and emphasizes a clinically recognizable syndromic phenotype in these patients.

}, keywords = {Animals, Cell Differentiation, Cell Movement, Child, Preschool, Chromosome Breakpoints, Disease Models, Animal, Embryonic Stem Cells, Female, Gene Expression, Gene Expression Profiling, Gene Expression Regulation, Developmental, Gene Knockdown Techniques, Genetic Association Studies, Haploinsufficiency, Humans, Intellectual Disability, Mediator Complex, Neural Crest, Neurons, Phenotype, RNA, Messenger, Sequence Analysis, DNA, Transcriptome, Translocation, Genetic, Zebrafish}, issn = {1098-1004}, doi = {10.1002/humu.22636}, author = {Utami, Kagistia Hana and Winata, Cecilia L and Hillmer, Axel M and Aksoy, Irene and Long, Hoang Truong and Liany, Herty and Chew, Elaine G Y and Mathavan, Sinnakaruppan and Tay, Stacey K H and Korzh, Vladimir and Sarda, Pierre and Davila, Sonia and Cacheux, Valere} } @article {33, title = {Genome wide analysis reveals Zic3 interaction with distal regulatory elements of stage specific developmental genes in zebrafish.}, journal = {PLoS Genet}, volume = {9}, year = {2013}, month = {2013 Oct}, pages = {e1003852}, abstract = {

Zic3 regulates early embryonic patterning in vertebrates. Loss of Zic3 function is known to disrupt gastrulation, left-right patterning, and neurogenesis. However, molecular events downstream of this transcription factor are poorly characterized. Here we use the zebrafish as a model to study the developmental role of Zic3 in vivo, by applying a combination of two powerful genomics approaches--ChIP-seq and microarray. Besides confirming direct regulation of previously implicated Zic3 targets of the Nodal and canonical Wnt pathways, analysis of gastrula stage embryos uncovered a number of novel candidate target genes, among which were members of the non-canonical Wnt pathway and the neural pre-pattern genes. A similar analysis in zic3-expressing cells obtained by FACS at segmentation stage revealed a dramatic shift in Zic3 binding site locations and identified an entirely distinct set of target genes associated with later developmental functions such as neural development. We demonstrate cis-regulation of several of these target genes by Zic3 using in vivo enhancer assay. Analysis of Zic3 binding sites revealed a distribution biased towards distal intergenic regions, indicative of a long distance regulatory mechanism; some of these binding sites are highly conserved during evolution and act as functional enhancers. This demonstrated that Zic3 regulation of developmental genes is achieved predominantly through long distance regulatory mechanism and revealed that developmental transitions could be accompanied by dramatic changes in regulatory landscape.

}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1003852}, author = {Winata, Cecilia L and Kondrychyn, Igor and Kumar, Vibhor and Srinivasan, Kandhadayar G and Orlov, Yuriy and Ravishankar, Ashwini and Prabhakar, Shyam and Stanton, Lawrence W and Korzh, Vladimir and Mathavan, Sinnakaruppan} } @article {36, title = {Zebrafish mRNA sequencing deciphers novelties in transcriptome dynamics during maternal to zygotic transition.}, journal = {Genome Res}, volume = {21}, year = {2011}, month = {2011 Aug}, pages = {1328-38}, abstract = {

Maternally deposited mRNAs direct early development before the initiation of zygotic transcription during mid-blastula transition (MBT). To study mechanisms regulating this developmental event in zebrafish, we applied mRNA deep sequencing technology and generated comprehensive information and valuable resources on transcriptome dynamics during early embryonic (egg to early gastrulation) stages. Genome-wide transcriptome analysis documented at least 8000 maternal genes and identified the earliest cohort of zygotic transcripts. We determined expression levels of maternal and zygotic transcripts with the highest resolution possible using mRNA-seq and clustered them based on their expression pattern. We unravel delayed polyadenylation in a large cohort of maternal transcripts prior to the MBT for the first time in zebrafish. Blocking polyadenylation of these transcripts confirms their role in regulating development from the MBT onward. Our study also identified a large number of novel transcribed regions in annotated and unannotated regions of the genome, which will facilitate reannotation of the zebrafish genome. We also identified splice variants with an estimated frequency of 50\%-60\%. Taken together, our data constitute a useful genomic information and valuable transcriptome resource for gene discovery and for understanding the mechanisms of early embryogenesis in zebrafish.

}, keywords = {Animals, Base Sequence, Genome, RNA, Messenger, RNA, Messenger, Stored, Sequence Analysis, RNA, Transcriptome, Zebrafish, Zebrafish Proteins, Zygote}, issn = {1549-5469}, doi = {10.1101/gr.116012.110}, author = {Aanes, H{\r a}vard and Winata, Cecilia L and Lin, Chi Ho and Chen, Jieqi P and Srinivasan, Kandhadayar G and Lee, Serene G P and Lim, Adrian Y M and Hajan, Hajira Shreen and Collas, Philippe and Bourque, Guillaume and Gong, Zhiyuan and Korzh, Vladimir and Alestr{\"o}m, Peter and Mathavan, Sinnakaruppan} } @article {65, title = {Transcriptome kinetics of arsenic-induced adaptive response in zebrafish liver.}, journal = {Physiol Genomics}, volume = {27}, year = {2006}, month = {2006 Nov 27}, pages = {351-61}, abstract = {

Arsenic is a prominent environmental toxicant and carcinogen; however, its molecular mechanism of toxicity and carcinogenicity remains poorly understood. In this study, we performed microarray-based expression profiling on liver of zebrafish exposed to 15 parts/million (ppm) arsenic [As(V)] for 8-96 h to identify global transcriptional changes and biological networks involved in arsenic-induced adaptive responses in vivo. We found that there was an increase of transcriptional activity associated with metabolism, especially for biosyntheses, membrane transporter activities, cytoplasm, and endoplasmic reticulum in the 96 h of arsenic treatment, while transcriptional programs for proteins in catabolism, energy derivation, and stress response remained active throughout the arsenic treatment. Many differentially expressed genes encoding proteins involved in heat shock proteins, DNA damage/repair, antioxidant activity, hypoxia induction, iron homeostasis, arsenic metabolism, and ubiquitin-dependent protein degradation were identified, suggesting strongly that DNA and protein damage as a result of arsenic metabolism and oxidative stress caused major cellular injury. These findings were comparable with those reported in mammalian systems, suggesting that the zebrafish liver coupled with the available microarray technology present an excellent in vivo toxicogenomic model for investigating arsenic toxicity. We proposed an in vivo, acute arsenic-induced adaptive response model of the zebrafish liver illustrating the relevance of many transcriptional activities that provide both global and specific information of a coordinated adaptive response to arsenic in the liver.

}, keywords = {Adaptation, Physiological, Animals, Arsenic, Down-Regulation, Gene Expression Profiling, Gene Expression Regulation, Genomics, Liver, Male, Metabolic Networks and Pathways, Oligonucleotide Array Sequence Analysis, Transcription, Genetic, Up-Regulation, Zebrafish}, issn = {1531-2267}, doi = {10.1152/physiolgenomics.00201.2005}, author = {Lam, Siew Hong and Winata, Cecilia L and Tong, Yan and Korzh, Svetlana and Lim, Wen San and Korzh, Vladimir and Spitsbergen, Jan and Mathavan, Sinnakarupan and Miller, Lance D and Liu, Edison T and Gong, Zhiyuan} }