Functional overlap of the dictyostelium RasG, RasD and RasB proteins

2000 ◽  
Vol 113 (8) ◽  
pp. 1427-1434 ◽  
Author(s):  
M. Khosla ◽  
G.B. Spiegelman ◽  
R. Insall ◽  
G. Weeks

Disruption of the rasG gene in Dictyostelium discoideum results in several distinct phenotypes: a defect in cytokinesis, reduced motility and reduced growth. Reintroduction of the rasG gene restores all of the properties of the rasG(-) cells to those of the wild type. To determine whether the defects are due to impaired interactions with a single or multiple downstream effectors, we tested the ability of the highly related but non identical Dictyostelium ras genes, rasD and rasB, to rescue the defects. Introduction of the rasD gene under the control of the rasG promoter into rasG null (rasG(-)) cells corrected all phenotypes except the motility defect, suggesting that motility is regulated by a RasG mediated pathway that is different to those regulating growth or cytokinesis. Western blot analysis of RasD protein levels revealed that vegetative rasG(-)cells contained considerably more protein than the parental AX-3 cells, suggesting that RasD protein levels are negatively regulated in vegetative cells by RasG. The level of RasD was enhanced when the rasD gene was introduced under the control of the rasG promoter, and this increase in protein is presumably responsible for the reversal of the growth and cytokinesis defects of the rasG(-)cells. Thus, RasD protein levels are controlled by the level of RasG, but not by the level of RasD. Introduction of the rasB gene under the control of the rasG promoter into rasG(-) cells produced a complex phenotype. The transformants were extremely small and mononucleate and exhibited enhanced motility. However, the growth of these cells was considerably slower than the growth of the rasG(-) cells, suggesting the possibility that high levels of RasB inhibit an essential process. This was confirmed by expressing rasB in wild-type cells; the resulting transformants exhibited severely impaired growth. When RasB protein levels were determined by western blot analysis, it was found that levels were higher in the rasG(-)cells than they were in the wild-type parental, suggesting that RasG also negatively regulates rasB expression in vegetative cells. Overexpression of rasB in the rasG(-)cells also reduced the level of RasD protein. In view of the fact that alternate Ras proteins correct some, but not all, of the defects exhibited by the rasG(-) cells, we propose that RasG interacts with more than one downstream effector. In addition, it is clear that the levels of the various Ras proteins are tightly regulated in vegetative cells and that overexpression can be deleterious.

2018 ◽  
Vol 22 ◽  
pp. 235-239
Author(s):  
O. V. Dmytruk ◽  
N. V. Bulbotka ◽  
A. A. Sibirny

Aim. The study of the mechanisms of fructose-1,6-bisphosphatase degradation in methylotrophic yeasts Pichia pastoris. Methods. Methods of determination the specific activity of fructose-1,6-bisphosphatase in the wild type and mutant strains of methylotrophic yeast P. pastoris after shifting cells from the medium with methanol into the medium with glucose were used. The study of fructose-1,6-bisphosphatase protein degradetion was performed by Western blot analysis. Results. The changes of the specific activity of fructose-1,6-bisphosphatase in the wild type strain GS200, the strain with the deletion of the GSS1 hexose sensor gene and strain defected in autophagy pathway SMD1163 of P. pastoris in short-term and long-term induction with methanol, and with or without the addition of the MG132 (proteasome degradation inhibitor) was investigated. Degradation of fructose‑1,6‑bisphosphatase by the Western blot analysis in GS200, SMD1163 and Δgss1 strains was studied. Conclusions. It was shown that the duration of cell incubation on methanol has no particular effect on the inactivation of the enzyme. The effect of the proteasome inhibitor MG132 was insignificant. Catabolic inactivation of cytosolic and peroxisomal enzymes is damaged in the Δgss1 mutant as glucose signaling is impaired. Fructose-1,6-bisphosphatase degrades by a vacuolar pathway, regardless of the duration of methanol induction, which correlates with the activity data of this enzyme. Keywords: fructose-1,6-bisphosphatase, yeasts, Pichia pastoris, methanol, autophagy.


2021 ◽  
pp. 096032712110061
Author(s):  
D Cao ◽  
L Chu ◽  
Z Xu ◽  
J Gong ◽  
R Deng ◽  
...  

Background: Visfatin acts as an oncogenic factor in numerous tumors through a variety of cellular processes. Visfatin has been revealed to promote cell migration and invasion in gastric cancer (GC). Snai1 is a well-known regulator of EMT process in cancers. However, the relationship between visfatin and snai1 in GC remains unclear. The current study aimed to explore the role of visfatin in GC. Methods: The RT-qPCR and western blot analysis were used to measure RNA and protein levels, respectively. The cell migration and invasion were tested by Trans-well assays and western blot analysis. Results: Visfatin showed upregulation in GC cells. Additionally, Visfatin with increasing concentration facilitated epithelial-mesenchymal transition (EMT) process by increasing E-cadherin and reducing N-cadherin and Vimentin protein levels in GC cells. Moreover, endogenous overexpression and knockdown of visfatin promoted and inhibited migratory and invasive abilities of GC cells, respectively. Then, we found that snai1 protein level was positively regulated by visfatin in GC cells. In addition, visfatin activated the NF-κB signaling to modulate snai1 protein expression. Furthermore, the silencing of snai1 counteracted the promotive impact of visfatin on cell migration, invasion and EMT process in GC. Conclusion: Visfatin facilitates cell migration, invasion and EMT process by targeting snai1 via the NF-κB signaling, which provides a potential insight for the treatment of GC.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4318-4318 ◽  
Author(s):  
Julian Baumeister ◽  
Nicolas Chatain ◽  
Annika Hubrich ◽  
Caroline Küstermann ◽  
Stephanie Sontag ◽  
...  

Abstract Myeloproliferative neoplasms (MPN) are a heterogeneous group of malignancies including polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). The JAK2V617F mutation can be found in 90% of PV and approximately 50% of ET and PMF patients. Hypoxia-inducible factors (HIFs) are master transcriptional regulators of the response to decreases in cellular oxygen levels. Unveiling the function of deregulated HIF-1 signaling in normal and malignant hematopoiesis was the aim of several recent publications, highlighting the importance of HIF-1 for the maintenance of leukemic stem cells (LSCs) in acute and chronic myeloid leukemia (AML/CML). In a JAK2V617F knock-in mouse model and in patients, JAK2V617F was shown to induce the accumulation of reactive oxygen species (ROS) in the hematopoietic stem cell compartment, leading to a stabilization of HIF-1α protein. Further, aberrant STAT5 and PI3K/AKT/mTOR signaling induced HIF-1α expression on the transcriptional and translational level. Ruxolitinib treatment inhibited growth and reduced the expression of HIF-1α and its target gene VEGF in the JAK2V617F human erythroleukemia cell line HEL. In several leukemic cell lines constitutive expression of HIF-1α was reported, even under normoxic conditions. However, it still remains unknown whether HIF-1α plays a role in JAK2V617F positive MPN. In this study, we investigated the role HIF-1α signaling in JAK2V617F positive MPN in vitro. We retrovirally transduced the murine bone marrow cell line 32D with JAK2V617F or JAK2WT. Western blot analysis revealed significant increases in HIF-1α protein levels in JAK2V617F positive cells compared to JAK2WT controls after cultivation in normoxic conditions and this effect was abrogated by treatment with the JAK1/JAK2 inhibitor ruxolitinib. Inhibition of HIF-1, binding to hypoxia response elements (HRE), by low doses of echinomycin (1 nM), significantly impaired proliferation and survival. Using an Annexin-V/7-AAD flow cytometry assay apoptosis was found to be selectively induced in JAK2V617F positive, but not JAK2WT cells after echinomycin treatment. Additionally, BrdU/7-AAD cell cycle analysis revealed that only JAK2V617F positive cells were significantly arrested in G0/1 phase. These findings were consistent with shRNA-mediated knockdown (KD) of HIF-1α in JAK2V617F transduced 32D cells in presence but not the absence of HIF-2 antagonist 2. Inhibition of HIF-2 was necessary due to a compensatory increase of HIF-2α protein levels, shown by Western Blot analysis, counteracting HIF-1α-KD mediated effects. We isolated PBMCs and BMMNCs from JAK2V617F positive patients or healthy controls using Ficoll density gradient centrifugation. Echinomycin significantly abrogated the colony formation ability alone and in combination with ruxolitinib. In vitro treatment with echinomycin significantly decreased cell number and viability of 8 JAK2V617F positive BMMNC samples (4 PV, 3 PMF, 1 preMF; p[1nM]=0.0169, p[5nM]=0.0009) and 7 PBMC samples (6 PV, 1 PMF; p[1nM]=0.0156, p[5nM]=0.0156) in a dose-dependent manner. In contrast, PBMCs from 6 healthy donors were unaffected by the treatment. The same effect was observed in heterozygous and homozygous iPS cell-derived progenitors from JAK2V617F positive PV patients, whereas JAK2WT cells were unaffected by the treatment. Collectively, our data indicate that targeting HIF-1 might represent a novel therapeutic approach in classical Philadelphia-chromosome-negative MPN. Disclosures Brümmendorf: Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Janssen: Consultancy; Merck: Consultancy; Takeda: Consultancy.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2549-2549
Author(s):  
Leticia Fröhlich Archangelo ◽  
Fabíola Traina ◽  
Philipp A Greif ◽  
Alexandre Maucuer ◽  
Valérie Manceau ◽  
...  

Abstract Abstract 2549 The CATS protein (also known as FAM64A and RCS1) was first identified as a novel CALM (PICALM) interactor that interacts with and influences the subcellular localization of CALM/AF10, a leukemic fusion protein found in acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL) and in malignant lymphoma. CATS is highly expressed in leukemia, lymphoma and tumor cell lines but not in non-proliferating T-cells or in peripheral blood lymphocytes (PBLs). The protein levels of CATS are cell cycle-dependent, induced by mitogens (e.g. PHA) and correlate with the proliferative state of the cell. Thus, CATS is as a marker for proliferation. Using CATS as a bait in a yeast two-hybrid screen we identified the Kinase Interacting Stathmin (KIS or UHMK1) as a CATS interacting partner. KIS is a serine/threonine kinase that positively regulates cell cycle progression through phosphorylation of p27KIP in leukemia cell lines. The interaction between CATS and KIS was confirmed by GST pull-down, and co-immunopreciptation. KIS interaction region was mapped to CATS N-terminal portion. Searching through the phosphorylation site databases PhosphoSitePlus™ (http://www.phosphosite.org) and Phosida (http://www.phosida.com/) we identified 9 residues within CATS shown to be subject of post-translational modification. Phosphorylation assay with recombinant KIS demonstrated that this kinase efficiently phosphorylated full length CATS and its N-terminal part, but not the C-terminal of the protein. To map the KIS phosphorylation site of CATS, peptides comprising all known phospho-sites of CATS N-terminal (S16, S129, S131, T133 and S135) and mutations of the putative KIS target motif (S129 and S131) were tested for KIS phosphorylation. Thereby, we identified CATS S131 as the unique target site for KIS phosphorylation. Western blot analysis of U2OS cells, which had undergone cell cycle synchronization by a double thymidine block, revealed that KIS fluctuated throughout the cell cycle and counteracted CATS levels. Furthermore, we analyzed KIS protein expression on bone marrow mononuclear cells (MNCs) of MDS and AML patients. We studied 5 healthy donors, 13 MDS patients (7 low-risk [RA/RARS] and 6 high-risk [RAEB/RAEBt] according to FAB classification) and 10 AML patients (7 de novo and 3 secondary). Western blot analysis revealed elevated levels of KIS in MDS and AML compared to the control samples. We used a reporter gene assay in order to determine the influence of KIS on the CATS-mediated transcriptional repression and to elucidate the role of KIS-dependent phosphorylation of CATS at serine 131 in this context. Coexpression of GAL4-DBD-CATS and KIS enhanced the inhibitory function of CATS on transactivation of the GAL4-tk-luciferase reporter. This effect of KIS was observed for both CATS wild type and CATS phospho-defective mutant (CATS S131A) but not when the kinase dead mutant KISK54R was used. Moreover, CATS phosphomimetic clone (CATSS131D) exerted the same transcriptional activity as the CATS wild type. These results demonstrate that KIS enhances the transcriptional repressor activity of CATS, and this effect is independent of CATS phosphorylation at S131 but dependent on the kinase activity of KIS. Finally, we investigated whether CATS would affect the CALM/AF10 function as an aberrant transcription factor. Coexpression of constant amounts of GAL4-DBD-CALM/AF10 and increasing amounts of CATS lead to reduced transactivation capacity of CALM/AF10 in a dose dependent manner. Our results show that CATS not only interacts with but is also a substrate for KIS, suggesting that CATS function might be modulated through phosphorylation events. The identification of the CATS-KIS interaction further supports the hypothesis that CATS plays an important role in the control of cell proliferation. Moreover the elevated levels of KIS in hematological malignances suggest that KIS could regulate CATS activity and/or function in highly proliferating leukemic cells. Thus our results indicate that CATS function might be important to understand the malignant transformation mediated by CALM/AF10. Disclosures: No relevant conflicts of interest to declare.


2002 ◽  
pp. 655-661 ◽  
Author(s):  
F Arturi ◽  
I Presta ◽  
D Scarpelli ◽  
JM Bidart ◽  
M Schlumberger ◽  
...  

BACKGROUND: Various clinical and experimental findings support the concept that human chorionic gonadotropin (hCG) can stimulate iodide uptake in thyroid cells. DESIGN: We investigated the molecular mechanisms underlying the effects of hCG on iodide uptake, and particularly its action on the expression of Na+/I- symporter (NIS) mRNA and protein. METHODS: Iodide uptake was analyzed in FTRL-5 cells by measuring (125)I concentrations in cells after a 30-min exposure to 0.1 microCi carrier-free Na (125)I in the presence or absence of hCG or, for control purposes, TSH. Expression of NIS mRNA and NIS protein synthesis were evaluated, respectively, with a semiquantitative 'multiplex' RT-PCR method and Western blot analysis. RESULTS: Iodide uptake was increased by hCG in a dose- and time-dependent manner: maximal effects were observed after 72 h of stimulation. The effect was cAMP dependent and paralleled that of TSH, although it lacked the early cycloheximide-independent component seen with TSH, and its peak effect was lower. Semiquantitative multiplex RT-PCR revealed that hCG produced a significant increase in NIS mRNA levels that was detectable after 4 h and peaked after 48 h. In contrast, in TSH-stimulated FRTL-5 cells, maximum NIS mRNA expression was observed after 24 h of stimulation. Western blot analysis demonstrated that hCG also caused a 2.5-fold increase over basal values in NIS protein levels, which was similar to that observed after TSH stimulation although the peak effects of the latter hormone were less marked and occurred earlier. CONCLUSION: Our data demonstrated that hCG stimulates iodide uptake in FRTL-5 cells by increasing NIS mRNA and protein levels. Thus, the functional status of the thyroid may be influenced by hCG-dependent changes in NIS expression occurring during pregnancy.


Biomedicines ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 532
Author(s):  
Daniele La Russa ◽  
Alessandro Marrone ◽  
Maurizio Mandalà ◽  
Rachele Macirella ◽  
Daniela Pellegrino

Caloric restriction (CR) represents a powerful intervention for extending healthspan and lifespan in several animal models, from yeast to primates. Additionally, in humans, CR has been found to induce cardiometabolic adaptations associated with improved health. In this study, we evaluated in an aged and obese rat model the effect of long-term (6 months) caloric restriction (−40%) on the oxidative/inflammatory balance in order to investigate the underlining mechanisms. In plasma, we analyzed the oxidative balance by photometric tests and the adiponectin/tumor necrosis factor-α-induced gene/protein 6 (TSG-6) levels by Western blot analysis. In the white adipose tissue, we examined the protein levels of AdipoR1, pAMPK, NFκB, NRF-2, and glutathione S-tranferase P1 by Western blot analysis. Our results clearly showed that caloric restriction significantly improves the plasmatic oxidative/inflammatory balance in parallel with a major increase in circulating adiponectin levels. Additionally, at the level of adipose tissue, we found a positive modulation of both anti-inflammatory and antioxidant pathways. These adaptations, induced by caloric restriction, with the achievement of normal weight, suggest that inflammatory and redox imbalance in obese aged rats appear to be more linked to obesity than to aging.


Author(s):  
Mengling Zhang ◽  
Jian Liu ◽  
Rui Zhang ◽  
Zengenni Liang ◽  
Shenghua Ding ◽  
...  

Background: Hypoxia is associated with abnormal cell apoptosis in trophoblast cells, which causes fetal growth restriction and related placental pathologies. Few effective methods for the prevention and treatment of placenta-related diseases exist. Natural products and functional foods have always been a rich source of potential anti-apoptotic drugs. Nobiletin (NOB), a hexamethoxyflavonoid derived from the citrus pomace, shows an anti-apoptotic activity, which is a non-toxic constituent of dietary phytochemicals approved by the Food and Drug Administration. However, their effects on hypoxia-induced human trophoblast cells have not been fully studied. Objective: The aim of this study was to investigate the protective effects of NOB on hypoxia-induced apoptosis of human trophoblast JEG-3 and BeWo cells, and their underlying mechanisms. Design: First, the protective effect of NOB on hypoxia-induced apoptosis of JEG-3 and BeWo cells was studied. Cell viability and membrane integrity were determined by CCK-8 assay and lactate dehydrogenase activity, respectively. Real Time Quantitative PCR (RT-qPCR) and Western blot analysis were used to detect the mRNA and protein levels of HIF1α. Propidium iodide (PI)-labeled flow cytometry was used to detect cell cycle distribution. Cell apoptosis was detected by flow cytometry with Annexin V-FITC and PI double staining, and the expression of apoptosis marker protein cl-PARP was detected by Western blot analysis. Then, the molecular mechanism of NOB against apoptosis was investigated. Computer molecular docking and dynamics were used to simulate the interaction between NOB and p53 protein, and this interaction was verified in vitro by Ultraviolet and visible spectrum (UV-visible spectroscopy), fluorescence spectroscopy and circular dichroism. Furthermore, the changes in the expression of p53 signaling pathway genes and proteins were detected by RT-qPCR and Western blot analysis, respectively. Results: Hypoxia treatment resulted in a decreased cell viability and cell membrane integrity in JEG-3 and BeWo cell lines, and an increased expression of HIF1α, cell cycle arrest in the G1 phase, and massive cell apoptosis, which were alleviated after NOB treatment. Molecular docking and dynamics simulations found that NOB spontaneously bonded to human p53 protein, leading to the change of protein conformation. The intermolecular interaction between NOB and human p53 protein was further confirmed by UV-visible spectroscopy, fluorescence spectroscopy and circular dichroism. After the treatment of 100 μM NOB, a down-regulation of mRNA and protein levels of p53 and p21 and an up-regulation of BCL2/BAX mRNA and protein ratio were observed in JEG-3 cells; however, there was also a down-regulation of mRNA and protein levels observed for p53 and p21 in BeWo cells after the treatment of NOB. The BCL2/BAX ratio of BeWo cells did not change after the treatment of 100 μM NOB. Conclusion: NOB attenuated hypoxia-induced apoptosis in JEG-3 and BeWo cell lines and might be a potential functional ingredient to prevent pregnancy-related diseases caused by hypoxia-induced apoptosis. These findings would also suggest the exploration and utilization of citrus resources, and the development of citrus industry.


2021 ◽  
Vol 11 (11) ◽  
pp. 1532
Author(s):  
Won-Hyeong Jeong ◽  
Wang-In Kim ◽  
Jin-Won Lee ◽  
Hyeng-Kyu Park ◽  
Min-Keun Song ◽  
...  

Transcranial alternating current stimulation (tACS) is a neuromodulation procedure that is currently studied for the purpose of improving cognitive function in various diseases. A few studies have shown positive effects of tACS in Alzheimer’s disease (AD). However, the mechanism underlying tACS has not been established. The purpose of this study was to investigate the mechanism of tACS in five familial AD mutation (5xFAD) mouse models. We prepared twenty 4-month-old mice and divided them into four groups: wild-type mice without stimulation (WT-NT group), wild-type mice with tACS (WT-T group), 5xFAD mice without stimulation (AD-NT group), and 5xFAD mice with tACS (AD-T group). The protocol implemented was as follows: gamma frequency 200 μA over the bilateral frontal lobe for 20 min over 2 weeks. The following tests were conducted: excitatory postsynaptic potential (EPSP) recording, Western blot analysis (cyclic AMP response element-binding (CREB) proteins, phosphorylated CREB proteins, brain-derived neurotrophic factor, and parvalbumin) to examine the synaptic plasticity. The EPSP was remarkably increased in the AD-T group compared with in the AD-NT group. In the Western blot analysis, the differences among the groups were not significant. Hence, tACS can affect the long-lasting enhancement of synaptic transmission in mice models of AD.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ji Che ◽  
Cuidi Xu ◽  
Yuanyuan Wu ◽  
Peiyu Jia ◽  
Qi Han ◽  
...  

Abstract Background Sarcopenia is a common skeletal disease related to myogenic disorders and muscle atrophy. Current clinical management has limited effectiveness. We sought to investigate the role of miR-1290 in myoblast differentiation and muscle atrophy. Methods By transfecting miR-1290 into C2C12 cells, we investigated whether miR-1290 regulates myogenesis and myotube atrophy via AKT/P70 signaling pathway. MHC staining was performed to assess myoblast differentiation. Differentiation-related MHC, Myod, and Myog protein levels, and atrophy-related MuRF1 and atrogin-1 were explored by western blot. An LPS-induced muscle atrophy rat model was developed. RT-PCR was conducted to analyze miR-1290 serum levels in muscle atrophy patients and normal controls (NCs). Results The miR-1290 transfection increased MHC-positive cells and MHC, Myod, and Myog protein levels in the miR-1290 transfection group, demonstrating that miR-1290 promoted C2C12 myoblast differentiation. Myotube diameter in the miR-1290 transfection group was higher than in the TNF-α-induced model group. Western blot analysis showed decreased MuRF1 and atrogin-1 levels in the miR-1290 transfection group compared with the model group, demonstrating that miR-1290 protected against myoblast cellular atrophy. Luciferase assay and western blot analysis showed that miR-1290 regulation was likely caused by AKT/p70/FOXO3 phosphorylation activation. In the LPS-induced muscle atrophy rat model, miR-1290 mimics ameliorated gastrocnemius muscle loss and increased muscle fiber cross-sectional area. Clinically, miR-1290 serum level was significantly decreased in muscle atrophy patients. Conclusions We found that miR-1290 enhances myoblast differentiation and inhibits myotube atrophy through Akt/p70/FoxO3 signaling in vitro and in vivo. In addition, miR-1290 may be a potential therapeutic target for sarcopenia treatment.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 608-608 ◽  
Author(s):  
Fiona C Brown ◽  
Michael Collett ◽  
Phillip J Robinson ◽  
James C Whisstock ◽  
Douglas J. Hilton ◽  
...  

Abstract Abstract 608 Forward-genetic screens have become a powerful method to study the pathogenesis of human disease and gene function. Chemical mutagenesis in mice using the mutagen, N-ethyl N-nitrosourea (ENU), has shown to be highly successful in elucidating novel genes or alleles in a variety of biological pathways, describing new functions of existing genes, and establishing mouse models that accurately recapitulate human disease. Advances in mapping strategies and deep sequencing technologies has dramatically simplified mutation detection, making ENU mutagenesis screens a feasible tool to study specific organ systems. To identify novel alleles regulating erythropoiesis, our laboratory has undertaken a dominant ENU mutagenesis screen. In this screen, the G1 progeny were screened at seven weeks of age for abnormalities in red cell indices (MCV, MCH, and HCT) using an automated hematological analyser. Here, we describe the identification of mice with a missense mutation of the large GTPase Dynamin 2 (DNM2) leading to an amino acid substitution V235G, predicted to lie within the nucleotide binding pocket for GTP. Western blot analysis for DNM2 protein revealed 50% protein levels in heterozygotes, suggesting that the point mutation leads to loss of protein rather than a dominant negative effect. Inherited DNM2 mutations are associated with autosomal dominant Charcot Tooth Myopathy (CTM) and Centronuclear Myopathy (CNM), but no recognised blood disorders. Heterozygous DNM2V235G displayed hypochromic, microcytic anemia – HGB (15 g/dl compared to 16.5 g/dl in wild type mice), MCV (41.3 fl compared to 45.6 fl in wild type mice) and MCH (12.7 pg compared to 14.5 pg in wild type mice), but no obvious neuropathy or myopathy. Homozygosity was lethal before embryonic (E) day 8.5. DNM2 is an essential component in clathrin-mediated endocytosis, which is required for uptake of transferrin into red cells for incorporation of heme. Accordingly, endocytosis assays for transferrin uptake by FACS and confocal microscopy revealed reduced uptake in heterozygotes, explaining the microcytic hypochromic anemia. Western blot analysis for ferritin demonstrated reduced cellular ferritin, indicating cellular iron deficiency. Thus, this mouse model provides the first in vivo evidence that haplo-insufficiency of DNM2 can lead to iron deficiency anemia. Disclosures: No relevant conflicts of interest to declare.


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