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Kala M, Babok S, Mikhailava N, Piirsoo M, Piirsoo A. The POU-HD TFs impede the replication efficiency of several human papillomavirus genomes. Virol J 2024; 21:54. [PMID: 38444021 PMCID: PMC10916165 DOI: 10.1186/s12985-024-02334-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/28/2024] [Indexed: 03/07/2024] Open
Abstract
Human papillomavirus (HPV) is a double-stranded DNA virus that infects cutaneous and mucosal epithelial cells. HPV replication initiates at the origin (ori), located within a noncoding region near the major early promoter. Only two viral proteins, E1 and E2, are essential for replication, with the host cell contributing other necessary factors. However, the role of host cell proteins in regulating HPV replication remains poorly understood. While several binding sites for cellular transcription factors (TFs), such as POU-HD proteins, have been mapped in the regulatory region, their functional importance is unclear. Some POU-HD TFs have been shown to influence replication in a system where E1 and E2 are provided exogenously. In this study, we investigated the impact of several POU-HD TFs on the replication of the HPV5, HPV11, and HPV18 genomes in U2OS cells and human primary keratinocytes. We demonstrated that OCT1, OCT6, BRN5A, and SKN1A are expressed in HPV host cells and that their overexpression inhibits HPV genome replication, whereas knocking down OCT1 had a positive effect. Using the replication-deficient HPV18-E1- genome, we demonstrated that OCT1-mediated inhibition of HPV replication involves modulation of HPV early promoters controlling E1 and E2 expression. Moreover, using Oct6 mutants deficient either in DNA binding or transcriptional regulation, we showed that the inhibition of HPV18 replication is solely dependent on Oct6's DNA binding activity. Our study highlights the complex regulatory roles of POU-HD factors in the HPV replication.
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Lototskaja E, Liblekas L, Piirsoo M, Laaneväli A, Ibragimov R, Piirsoo A. Phosphorylation of E2 Serine Residue 402 Is Required for the Transcription and Replication of the HPV5 Genome. J Virol 2023; 97:e0064323. [PMID: 37272841 PMCID: PMC10308906 DOI: 10.1128/jvi.00643-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 05/13/2023] [Indexed: 06/06/2023] Open
Abstract
Cutaneous human papillomavirus type 5 (HPV5) belongs to the supposedly oncogenic β-HPVs associated with specific types of skin and oral cavity cancers. Three viral proteins, namely, helicase E1 and transcription factors E2 and E8^E2, are master regulators of the viral life cycle. HPV5 E2 is a transcriptional activator that also participates in the E1-dependent replication and nuclear retention of the viral genome, whereas E8^E2 counterbalances the activity of E2 and inhibits HPV transcription and replication. In the present study, we demonstrate that the HPV5 E2 protein is extensively phosphorylated by cellular protein kinases, and serine residue 402 (S402) is the highest scoring phosphoacceptor site. This residue is located within a motif conserved among many β-HPVs and in the oncogenic HPV31 α-type. Using the nonphosphorylatable and phosphomimetic mutants, we demonstrate that phosphorylation of the E2 S402 residue is required for the transcription and replication of the HPV5 genome in U2OS cells and human primary keratinocytes. Mechanistically, the E2-S402-phopshodeficient protein is unable to trigger viral gene transcription and has an impaired ability to support E1-dependent replication, but the respective E8^E2-S213 mutant displays no phenotype. However, phosphorylation of the E2 S402 residue has no impact on the E2 stability, subcellular localization, self-assembly, DNA-binding capacity, and affinity to the E1 and BRD4 proteins. Further studies are needed to identify the protein kinase(s) responsible for this phosphorylation. IMPORTANCE Human papillomavirus type 5 (HPV5) may play a role in the development of specific types of cutaneous and head and neck cancers. The persistence of the HPV genome in host cells depends on the activity of its proteins, namely, a helicase E1 and transcription/replication factor E2. The latter also facilitates the attachment of episomal viral genomes to host cell chromosomes. In the present study, we show that the HPV5 E2 protein is extensively phosphorylated by host cell protein kinases, and we identify serine residue 402 as the highest scoring phosphoacceptor site of E2. We demonstrate that the replication of the HPV5 genome may be blocked by a single point mutation that prevents phosphorylation of this serine residue and switches off the transcriptional activity of the E2 protein. The present study contributes to a better understanding of β-HPV5 replication and its regulation by host cell protein kinases.
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Tisler A, Stirrup O, Pisarev H, Kalda R, Meister T, Suija K, Kolde R, Piirsoo M, Uusküla A. Post-acute sequelae of COVID-19 among hospitalized patients in Estonia: Nationwide matched cohort study. PLoS One 2022; 17:e0278057. [PMID: 36417409 PMCID: PMC9683565 DOI: 10.1371/journal.pone.0278057] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 11/09/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Post-acute COVID-19 sequelae refers to a variety of health complications involving different organ systems that have been described among individuals after acute phase of illness. Data from unselected population groups with long-time follow up is needed to comprehensively describe the full spectrum of post-acute COVID-19 complications. METHODS In this retrospective nationwide cohort study, we used data obtained from electronic health record database. Our primary cohort were adults hospitalized with confirmed COVID-19 and matched (age, sex, Charlson Comorbidity Index) unaffected controls from general population. Individuals included from February 2020 until March 2021 were followed up for 12 months. We estimated risks of all-cause mortality, readmission and incidence of 16 clinical sequelae after acute COVID-19 phase. Using a frailty Cox model, we compared incidences of outcomes in two cohorts. RESULTS The cohort comprised 3949 patients older than 18 years who were alive 30 days after COVID-19 hospital admission and 15511 controls. Among cases 40.3% developed at least one incident clinical sequelae after the acute phase of SARS-CoV-2 infection, which was two times higher than in general population group. We report substantially higher risk of all-cause mortality (adjusted hazard ratio (aHR) = 2.57 (95%CI 2.23-2.96) and hospital readmission aHR = 1.73 (95%CI 1.58-1.90) among hospitalized COVID-19 patients. We found that the risks for new clinical sequalae were significantly higher in COVID-19 patients than their controls, especially for dementia aHR = 4.50 (95% CI 2.35-8.64), chronic lower respiratory disease aHR = 4.39 (95% CI 3.09-6.22), liver disease aHR 4.20 (95% CI 2.01-8.77) and other (than ischemic) forms of heart diseases aHR = 3.39 (95%CI 2.58-4.44). CONCLUSION Our results provide evidence that the post-acute COVID-19 morbidity within the first year after COVID-19 hospitalization is substantial. Risks of all-cause mortality, hospitalisation and majority of clinical sequelae were significantly higher in hospitalized COVID-19 patients than in general population controls and warrant targeted prevention efforts.
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Uusküla A, Jürgenson T, Pisarev H, Kolde R, Meister T, Tisler A, Suija K, Kalda R, Piirsoo M, Fischer K. Long-term mortality following SARS-CoV-2 infection: A national cohort study from Estonia. THE LANCET REGIONAL HEALTH. EUROPE 2022; 18:100394. [PMID: 35505834 PMCID: PMC9051903 DOI: 10.1016/j.lanepe.2022.100394] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
BACKGROUND The objective of this study was to describe 12-month mortality following SARS-CoV-2 infection compared with a reference population with no history of SARS-CoV-2. METHODS Nationwide cohort study using electronic health care data on SARS-CoV-2 RNA positive cases (n= 66,287) and reference group subjects (n=254,969) with linkage to SARS-CoV-2 testing and death records. FINDINGS People infected with SARS-COV-2 had more than three times the risk of dying over the following year compared with those who remained uninfected (aHR 3·1, 95%CI 2·9-3·3). Short-term mortality (up to 5 weeks post-infection) was significantly higher among COVID-19 group (1623·0/10 000) than in the reference group (118/10 000). For COVID-19 cases aged 60 years or older, increased mortality persisted until the end of the first year after infection, and was related to increased risk for cardiovascular (aHR 2·1, 95%CI 1·8-2·3), cancer (aHR 1·5, 95%CI 1·2-1·9), respiratory system diseases (aHR 1·9, 95%CI 1·2-3·0), and other causes of death (aHR 1·8, 95%CI 1·4-2·2). INTERPRETATION Increased risk of death from SARS-CoV-2 is not limited to the acute illness: SARS-CoV-2 infection carries a substantially increased mortality in the following 12 months. This excess death mainly occurs in older people and is driven by broad array of causes of death. FUNDING Research was carried out with the support of Estonian Research Council (grants PRG1197, PRG198), European Regional Development Fund (RITA 1/02-120) and European Social Fund via IT Academy program.
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Liblekas L, Piirsoo A, Laanemets A, Tombak EM, Laaneväli A, Ustav E, Ustav M, Piirsoo M. Analysis of the Replication Mechanisms of the Human Papillomavirus Genomes. Front Microbiol 2021; 12:738125. [PMID: 34733254 PMCID: PMC8558456 DOI: 10.3389/fmicb.2021.738125] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/22/2021] [Indexed: 11/27/2022] Open
Abstract
The life-cycle of human papillomaviruses (HPVs) includes three distinct phases of the viral genome replication. First, the viral genome is amplified in the infected cells, and this amplification is often accompanied by the oligomerization of the viral genomes. Second stage includes the replication of viral genomes in concert with the host cell genome. The viral genome is further amplified during the third stage of the viral-life cycle, which takes place only in the differentiated keratinocytes. We have previously shown that the HPV18 genomes utilize at least two distinct replication mechanisms during the initial amplification. One of these mechanisms is a well-described bidirectional replication via theta type of replication intermediates. The nature of another replication mechanism utilized by HPV18 involves most likely recombination-dependent replication. In this paper, we show that the usage of different replication mechanisms is a property shared also by other HPV types, namely HPV11 and HPV5. We further show that the emergence of the recombination dependent replication coincides with the oligomerization of the viral genomes and is dependent on the replicative DNA polymerases. We also show that the oligomeric genomes of HPV18 replicate almost exclusively using recombination dependent mechanism, whereas monomeric HPV31 genomes replicate bi-directionally during the maintenance phase of the viral life-cycle.
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Piirsoo A, Pink A, Kasak L, Kala M, Kasvandik S, Ustav M, Piirsoo M. Differential phosphorylation determines the repressor and activator potencies of GLI1 proteins and their efficiency in modulating the HPV life cycle. PLoS One 2019; 14:e0225775. [PMID: 31770404 PMCID: PMC6879148 DOI: 10.1371/journal.pone.0225775] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/12/2019] [Indexed: 11/19/2022] Open
Abstract
The Sonic Hedgehog (Shh) signalling pathway plays multiple roles during embryonic development and under pathological conditions. Although the core components of the Shh pathway are conserved, the regulation of signal transduction varies significantly among species and cell types. Protein kinases Ulk3 and Pka are involved in the Shh pathway as modulators of the activities of Gli transcription factors, which are the nuclear mediators of the signal. Here, we investigate the regulation and activities of two GLI1 isoforms, full-length GLI1 (GLI1FL) and GLI1ΔN. The latter protein lacks the first 128 amino acids including the conserved phosphorylation cluster and the binding motif for SUFU, the key regulator of GLI activity. Both GLI1 isoforms are co-expressed in all human cell lines analysed and possess similar DNA binding activity. ULK3 potentiates the transcriptional activity of both GLI1 proteins, whereas PKA inhibits the activity of GLI1ΔN, but not GLI1FL. In addition to its well-established role as a transcriptional activator, GLI1FL acts as a repressor by inhibiting transcription from the early promoters of human papillomavirus type 18 (HPV18). Additionally, compared to GLI1ΔN, GLI1FL is a more potent suppressor of replication of several HPV types. Altogether, our data show that the N-terminal part of GLI1FL is crucial for the realization of its full potential as a transcriptional regulator.
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Piirsoo A, Piirsoo M, Kala M, Sankovski E, Lototskaja E, Levin V, Salvi M, Ustav M. Activity of CK2α protein kinase is required for efficient replication of some HPV types. PLoS Pathog 2019; 15:e1007788. [PMID: 31091289 PMCID: PMC6538197 DOI: 10.1371/journal.ppat.1007788] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 05/28/2019] [Accepted: 04/24/2019] [Indexed: 12/14/2022] Open
Abstract
Inhibition of human papillomavirus (HPV) replication is a promising therapeutic approach for intervening with HPV-related pathologies. Primary targets for interference are two viral proteins, E1 and E2, which are required for HPV replication. Both E1 and E2 are phosphoproteins; thus, the protein kinases that phosphorylate them might represent secondary targets to achieve inhibition of HPV replication. In the present study, we show that CX4945, an ATP-competitive small molecule inhibitor of casein kinase 2 (CK2) catalytic activity, suppresses replication of different HPV types, including novel HPV5NLuc, HPV11NLuc and HPV18NLuc marker genomes, but enhances the replication of HPV16 and HPV31. We further corroborate our findings using short interfering RNA (siRNA)-mediated knockdown of CK2 α and α' subunits in U2OS and CIN612 cells; we show that while both subunits are expressed in these cell lines, CK2α is required for HPV replication, but CK2α' is not. Furthermore, we demonstrate that CK2α acts in a kinase activity-dependent manner and regulates the stability and nuclear retention of endogenous E1 proteins of HPV11 and HPV18. This unique feature of CK2α makes it an attractive target for developing antiviral agents.
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Taal K, Tuvikene J, Rullinkov G, Piirsoo M, Sepp M, Neuman T, Tamme R, Timmusk T. Neuralized family member NEURL1 is a ubiquitin ligase for the cGMP-specific phosphodiesterase 9A. Sci Rep 2019; 9:7104. [PMID: 31068605 PMCID: PMC6506465 DOI: 10.1038/s41598-019-43069-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 04/01/2019] [Indexed: 11/15/2022] Open
Abstract
Neuralized functions as a positive regulator of the Notch pathway by promoting ubiquitination of Notch ligands via its E3 ligase activity, resulting in their efficient endocytosis and signaling. Using a yeast two-hybrid screen, we have identified a cGMP-hydrolysing phosphodiesterase, PDE9A, as a novel interactor and substrate of Neuralized E3 ubiquitin protein ligase 1 (NEURL1). We confirmed this interaction with co-immunoprecipitation experiments and show that both Neuralized Homology Repeat domains of NEURL1 can interact with PDE9A. We also demonstrate that NEURL1 can promote polyubiquitination of PDE9A that leads to its proteasome-mediated degradation mainly via lysine residue K27 of ubiquitin. Our results suggest that NEURL1 acts as a novel regulator of protein levels of PDE9A.
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Kasak L, Näks M, Eek P, Piirsoo A, Bhadoria R, Starkov P, Saarma M, Kasvandik S, Piirsoo M. Characterization of Protein Kinase ULK3 Regulation by Phosphorylation and Inhibition by Small Molecule SU6668. Biochemistry 2018; 57:5456-5465. [DOI: 10.1021/acs.biochem.8b00356] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Piirsoo A, Kasak L, Kauts ML, Loog M, Tints K, Uusen P, Neuman T, Piirsoo M. Protein kinase inhibitor SU6668 attenuates positive regulation of Gli proteins in cancer and multipotent progenitor cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:703-14. [PMID: 24418624 PMCID: PMC3946003 DOI: 10.1016/j.bbamcr.2014.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 12/18/2013] [Accepted: 01/02/2014] [Indexed: 11/16/2022]
Abstract
Observations that Glioma-associated transcription factors Gli1 and Gli2 (Gli1/2), executers of the Sonic Hedgehog (Shh) signaling pathway and targets of the Transforming Growth Factor β (TGF-β) signaling axis, are involved in numerous developmental and pathological processes unveil them as attractive pharmaceutical targets. Unc-51-like serine/threonine kinase Ulk3 has been suggested to play kinase activity dependent and independent roles in the control of Gli proteins in the context of the Shh signaling pathway. This study aimed at investigating whether the mechanism of generation of Gli1/2 transcriptional activators has similarities regardless of the signaling cascade evoking their activation. We also elucidate further the role of Ulk3 kinase in regulation of Gli1/2 proteins and examine SU6668 as an inhibitor of Ulk3 catalytic activity and a compound targeting Gli1/2 proteins in different cell-based experimental models. Here we demonstrate that Ulk3 is required not only for maintenance of basal levels of Gli1/2 proteins but also for TGF-β or Shh dependent activation of endogenous Gli1/2 proteins in human adipose tissue derived multipotent stromal cells (ASCs) and mouse immortalized progenitor cells, respectively. We show that cultured ASCs possess the functional Shh signaling axis and differentiate towards osteoblasts in response to Shh. Also, we demonstrate that similarly to Ulk3 RNAi, SU6668 prevents de novo expression of Gli1/2 proteins and antagonizes the Gli-dependent activation of the gene expression programs induced by either Shh or TGF-β. Our data suggest SU6668 as an efficient inhibitor of Ulk3 kinase allowing manipulation of the Gli-dependent transcriptional outcome.
Ulk3 is involved in the maintenance of Gli1/2 expression. SU6668 prevents de novo expression of Gli1/2 proteins induced by Shh or TGF-β. SU6668 inhibits up-regulation of Gli1/2 proteins via Ulk3. Human ASCs differentiate towards osteoblasts in response to Shh.
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Maloverjan A, Piirsoo M. Mammalian homologues of Drosophila fused kinase. VITAMINS AND HORMONES 2012; 88:91-113. [PMID: 22391301 DOI: 10.1016/b978-0-12-394622-5.00005-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Sonic Hedgehog (Shh) signaling pathway is implicated in various developmental and postnatal processes. Much of the current knowledge about the mechanisms of Shh signal transduction in vertebrates comes from the investigations of the respective pathway in fruit fly Drosophila melanogaster. In Drosophila, serine/threonine kinase fused is involved in all aspects of regulation of the Hh-dependent transcription factor cubitus interruptus possessing both catalytic and regulatory functions. Two proteins, Stk36 and Ulk3, share similarity with fu and have been suggested as mammalian fu homologues. However, in vivo data clarify that Stk36 is not required for embryonic development in mice and participates in Shh-independent genesis of motile cilia. Even if Stk36 is associated with any pathological or physiological aspect of postnatal Shh signaling in mammals, it has perhaps only regulatory functions since its catalytic activity seems to be lost during evolution. In contrast to Stk36, Ulk3 is an active kinase. In non-stimulated cells, Ulk3 catalytic activity is blocked, and it is involved in negative control of Gli proteins, mediators of Shh signaling. In response to Shh, Ulk3 positively regulates Gli proteins by directly phosphorylating them. Thus, Ulk3 is able to recapitulate both positive and negative roles of fu in vitro. However, Ulk3 functioning in vivo remains to be investigated.
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Maloverjan A, Piirsoo M, Kasak L, Peil L, Østerlund T, Kogerman P. Dual function of UNC-51-like kinase 3 (Ulk3) in the Sonic hedgehog signaling pathway. J Biol Chem 2010; 285:30079-90. [PMID: 20643644 DOI: 10.1074/jbc.m110.133991] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Sonic hedgehog (Shh) signaling pathway controls a variety of developmental processes and is implicated in tissue homeostasis maintenance and neurogenesis in adults. Recently, we identified Ulk3 as an active kinase able to positively regulate Gli proteins, mediators of the Shh signaling in mammals. Here, we provide several lines of evidence that Ulk3 participates in the transduction of the Shh signal also independently of its kinase activity. We demonstrate that Ulk3 through its kinase domain interacts with Suppressor of Fused (Sufu), a protein required for negative regulation of Gli proteins. Sufu blocks Ulk3 autophosphorylation and abolishes its ability to phosphorylate and positively regulate Gli proteins. We show that Shh signaling destabilizes the Sufu-Ulk3 complex and induces the release of Ulk3. We demonstrate that the Sufu-Ulk3 complex, when co-expressed with Gli2, promotes generation of the Gli2 repressor form, and that reduction of the Ulk3 mRNA level in Shh-responsive cells results in higher potency of the cells to transmit the Shh signal. Our data suggests a dual function of Ulk3 in the Shh signal transduction pathway and propose an additional way of regulating Gli proteins by Sufu, through binding to and suppression of Ulk3.
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Maloverjan A, Piirsoo M, Michelson P, Kogerman P, Østerlund T. Identification of a novel serine/threonine kinase ULK3 as a positive regulator of Hedgehog pathway. Exp Cell Res 2010; 316:627-37. [DOI: 10.1016/j.yexcr.2009.10.018] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 10/12/2009] [Accepted: 10/16/2009] [Indexed: 11/29/2022]
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Piirsoo M, Kaljas A, Tamm K, Timmusk T. Expression of NGF and GDNF family members and their receptors during peripheral nerve development and differentiation of Schwann cells in vitro. Neurosci Lett 2009; 469:135-40. [PMID: 19944743 PMCID: PMC2808476 DOI: 10.1016/j.neulet.2009.11.060] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 11/17/2009] [Accepted: 11/23/2009] [Indexed: 01/13/2023]
Abstract
Ligands of NGF and GDNF families of neurotrophic factors have important functions in the development of the vertebrate peripheral nervous system (PNS). It has been established that they also play key roles in the regeneration of PNS. Expression patterns of NGF and GDNF family members and their receptors have mostly been analyzed during regeneration, and less during development of the PNS. We describe the expression of mRNAs encoding these neurotrophic factors and their receptors during development of rat sciatic nerve and in three modes of differentiation of cultured rat Schwann cells. Our results demonstrate specific expression patterns of NGF and GDNF family ligands and their receptors during differentiation of Schwann cells in vivo and in vitro.
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Aid T, Kazantseva A, Piirsoo M, Palm K, Timmusk T. Mouse and rat BDNF gene structure and expression revisited. J Neurosci Res 2007; 85:525-35. [PMID: 17149751 PMCID: PMC1878509 DOI: 10.1002/jnr.21139] [Citation(s) in RCA: 745] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) has important functions in the development of the nervous system and in brain plasticity-related processes such as memory, learning, and drug addiction. Despite the fact that the function and regulation of rodent BDNF gene expression have received close attention during the last decade, knowledge of the structural organization of mouse and rat BDNF gene has remained incomplete. We have identified and characterized several mouse and rat BDNF transcripts containing novel 5' untranslated exons and introduced a new numbering system for mouse and rat BDNF exons. According to our results both mouse and rat BDNF gene consist of eight 5' untranslated exons and one protein coding 3' exon. Transcription of the gene results in BDNF transcripts containing one of the eight 5' exons spliced to the protein coding exon and in a transcript containing only 5' extended protein coding exon. We also report the distinct tissue-specific expression profiles of each of the mouse and rat 5' exon-specific transcripts in different brain regions and nonneural tissues. In addition, we show that kainic acid-induced seizures that lead to changes in cellular Ca(2+) levels as well as inhibition of DNA methylation and histone deacetylation contribute to the differential regulation of the expression of BDNF transcripts. Finally, we confirm that mouse and rat BDNF gene loci do not encode antisense mRNA transcripts, suggesting that mechanisms of regulation for rodent and human BDNF genes differ substantially.
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Jaegle M, Ghazvini M, Mandemakers W, Piirsoo M, Driegen S, Levavasseur F, Raghoenath S, Grosveld F, Meijer D. The POU proteins Brn-2 and Oct-6 share important functions in Schwann cell development. Genes Dev 2003; 17:1380-91. [PMID: 12782656 PMCID: PMC196070 DOI: 10.1101/gad.258203] [Citation(s) in RCA: 224] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The genetic hierarchy that controls myelination of peripheral nerves by Schwann cells includes the POU domain Oct-6/Scip/Tst-1and the zinc-finger Krox-20/Egr2 transcription factors. These pivotal transcription factors act to control the onset of myelination during development and tissue regeneration in adults following damage. In this report we demonstrate the involvement of a third transcription factor, the POU domain factor Brn-2. We show that Schwann cells express Brn-2 in a developmental profile similar to that of Oct-6 and that Brn-2 gene activation does not depend on Oct-6. Overexpression of Brn-2 in Oct-6-deficient Schwann cells, under control of the Oct-6 Schwann cell enhancer (SCE), results in partial rescue of the developmental delay phenotype, whereas compound disruption of both Brn-2 and Oct-6 results in a much more severe phenotype. Together these data strongly indicate that Brn-2 function largely overlaps with that of Oct-6 in driving the transition from promyelinating to myelinating Schwann cells.
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Männik A, Piirsoo M, Nordström K, Ustav E, Vennström B, Ustav M. Effective generation of transgenic mice by Bovine papillomavirus type 1 based self-replicating plasmid that is maintained as extrachromosomal genetic element in three generations of animals. Plasmid 2003; 49:193-204. [PMID: 12749834 DOI: 10.1016/s0147-619x(03)00012-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The objective of our study was to analyze the efficiency and the properties of the inheritance of the Bovine papillomavirus type 1 (BPV1) replicator-based plasmid used as vector system for generation of transgenic animals. Previously, we have characterized a series of self-replicating plasmid vectors containing all viral factors necessary and sufficient for stable extrachromosomal replication of the BPV1 genome in the tissue culture system. We also demonstrated that the designed replicating vector system has a considerable benefit in the transgene expression, if compared to the regular expression vector. The vector, which showed the highest stability and maintenance function in the tissue culture was chosen for generation of the transgenic mice by pronuclear injections of the circular supercoiled plasmid. This method resulted in successful production of transgenic animals. Transmission efficiency of the vectors into the F(1) generation of animals varied between 0 and 48%, whereas transmission into the F(2) generation was uniformly near 50%. The maintenance of the vector-plasmids in the F(2) generation of transgenic animals as extrachromosomal genetic element was demonstrated by rescue of the plasmid into the Escherichia coli.
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Ghazvini M, Mandemakers W, Jaegle M, Piirsoo M, Driegen S, Koutsourakis M, Smit X, Grosveld F, Meijer D. A cell type-specific allele of the POU gene Oct-6 reveals Schwann cell autonomous function in nerve development and regeneration. EMBO J 2002; 21:4612-20. [PMID: 12198163 PMCID: PMC125415 DOI: 10.1093/emboj/cdf475] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
While an important role for the POU domain transcription factor Oct-6 in the developing peripheral nerve has been well established, studies into its exact role in nerve development and regeneration have been hampered by the high mortality rate of newborn Oct-6 mutant animals. In this study we have generated a Schwann cell-specific Oct-6 allele through deletion of the Schwann cell-specific enhancer element (SCE) in the Oct-6 locus. Analysis of mice homozygous for this allele (deltaSCE allele) reveals that rate-limiting levels of Oct-6 in Schwann cells are dependent on the SCE and that this element does not contribute to Oct-6 regulation in other cell types. We demonstrate a Schwann cell autonomous function for Oct-6 during nerve development as well as in regenerating nerve. Additionally, we show that Krox-20, an important regulatory target of Oct-6 in Schwann cells, is activated, with delayed kinetics, through an Oct-6-independent mechanism in these mice.
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Piirsoo M, Ustav E, Mandel T, Stenlund A, Ustav M. Cis and trans requirements for stable episomal maintenance of the BPV-1 replicator. EMBO J 1996. [DOI: 10.1002/j.1460-2075.1996.tb00328.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Piirsoo M, Ustav E, Mandel T, Stenlund A, Ustav M. Cis and trans requirements for stable episomal maintenance of the BPV-1 replicator. EMBO J 1996; 15:1-11. [PMID: 8598191 PMCID: PMC449912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Papillomavirus genomes are maintained as multicopy nuclear plasmids in transformed cells. To address the mechanisms by which the viral DNA is stably propagated in the transformed cells, we have constructed a cell line CH04.15 expressing constitutively the viral proteins E1 and E2, that are required for initiation of viral DNA replication. We show that these viral proteins are necessary and sufficient for stable extrachromosomal replication. Using the cell line CH04.15, we have shown that the bovine papillomavirus-1 (BPV-1) minimal origin of replication (MO) is absolutely necessary, but is not sufficient for stable extrachromosomal replication of viral plasmids. By deletion and insertion analysis, we identified an additional element (minichromosome maintenance element, MME) in the upstream regulatory region of BPV-1 which assures stable replication of the MO-containing plasmids. This element is composed of multiple binding sites for the transcription activator E2. MME appears to function in the absence of replication but requires E1 and E2 proteins for activity. In contrast to, for example, Epstein-Barr virus oriP, stably maintained BPV-1 plasmids are not subject to once-per-cell cycle replication as determined by density labelling experiments. These results indicate that papillomavirus episomal replicators replicate independently of the chromosomal DNA of their hosts.
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