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1.
Lancet Haematol ; 11(7): e487-e498, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38824932

RESUMO

BACKGROUND: Iadademstat is a potent, selective, oral inhibitor of both the enzymatic and scaffolding activities of the transcriptional repressor lysine-specific demethylase 1 (LSD1; also known as KDM1A) that showed promising early activity and safety in a phase 1 trial and strong preclinical synergy with azacitidine in acute myeloid leukaemia cell lines. Therefore, we aimed to investigate the combination of iadademstat and azacitidine for the treatment of adult patients with newly diagnosed acute myeloid leukaemia. METHODS: The open-label, phase 2a, dose-finding ALICE study was conducted at six hospitals in Spain and enrolled patients aged 18 years or older with newly diagnosed acute myeloid leukaemia not eligible for intensive chemotherapy and an ECOG performance status of 0-2. In the dose escalation portion of the trial, patients received a starting dose of iadademstat at 90 µg/m2 per day (with de-escalation to 60 µg/m2 per day and escalation up to 140 µg/m2 per day) orally, for 5 days on, 2 days off weekly, with azacitidine 75 mg/m2 subcutaneously, for seven of 28 days. The primary objectives were safety (analysed in the safety analysis set; all patients who received at least one dose of study treatment) and establishing the recommended phase 2 dose; secondary objectives included response rates in the efficacy analysis set (all patients who had at least one efficacy assessment). This study is registered on EudraCT (EudraCT 2018-000482-36) and has been completed. FINDINGS: Between Nov 12, 2018, and Sept 30, 2021, 36 patients with newly diagnosed acute myeloid leukaemia were enrolled; the median age was 76 (IQR 74-79) years, all patients were White, 18 (50%) were male, and 18 (50%) were female, and all had intermediate-risk or adverse-risk acute myeloid leukaemia. The median follow-up was 22 (IQR 16-31) months. The most frequent (≥10%) adverse events considered to be related to treatment were decreases in platelet (25 [69%]) and neutrophil (22 [61%]) counts (all grade 3-4) and anaemia (15 [42%]; of which ten [28%] were grade 3-4). Three patients had treatment-related serious adverse events (one fatal grade 5 intracranial haemorrhage, one grade 3 differentiation syndrome, and one grade 3 febrile neutropenia). Based on safety, pharmacokinetic and pharmacodynamic data, and efficacy, the recommended phase 2 dose of iadademstat was 90 µg/m2 per day with azacitidine. 22 (82%; 95% CI 62-94) of 27 patients in the efficacy analysis set had an objective response. 14 (52%) of 27 patients had complete remission or complete remission with incomplete haematological recovery; of these, ten of 11 evaluable for measurable residual disease achieved negativity. In the safety analysis set, 22 (61%) of 36 patients had an objective response. INTERPRETATION: The combination of iadademstat and azacitidine has a manageable safety profile and shows promising responses in patients with newly diagnosed acute myeloid leukaemia, including those with high-risk prognostic factors. FUNDING: Oryzon Genomics and Spain's Ministerio de Ciencia, Innovacion y Universidades (MICIU)-Agencia Estatal de Investigacion (AEI).


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Azacitidina , Leucemia Mieloide Aguda , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Azacitidina/uso terapêutico , Azacitidina/administração & dosagem , Azacitidina/efeitos adversos , Masculino , Feminino , Idoso , Pessoa de Meia-Idade , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Histona Desmetilases/antagonistas & inibidores , Adulto , Relação Dose-Resposta a Droga , Idoso de 80 Anos ou mais , Cicloexanos , Diaminas
2.
Pharmaceutics ; 14(7)2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35890315

RESUMO

Lysine specific demethylase 1 (LSD1; also known as KDM1A), is an epigenetic modulator that modifies the histone methylation status. KDM1A forms a part of protein complexes that regulate the expression of genes involved in the onset and progression of diseases such as cancer, central nervous system (CNS) disorders, viral infections, and others. Vafidemstat (ORY-2001) is a clinical stage inhibitor of KDM1A in development for the treatment of neurodegenerative and psychiatric diseases. However, the role of ORY-2001 targeting KDM1A in neuroinflammation remains to be explored. Here, we investigated the effect of ORY-2001 on immune-mediated and virus-induced encephalomyelitis, two experimental models of multiple sclerosis and neuronal damage. Oral administration of ORY-2001 ameliorated clinical signs, reduced lymphocyte egress and infiltration of immune cells into the spinal cord, and prevented demyelination. Interestingly, ORY-2001 was more effective and/or faster acting than a sphingosine 1-phosphate receptor antagonist in the effector phase of the disease and reduced the inflammatory gene expression signature characteristic ofEAE in the CNS of mice more potently. In addition, ORY-2001 induced gene expression changes concordant with a potential neuroprotective function in the brain and spinal cord and reduced neuronal glutamate excitotoxicity-derived damage in explants. These results pointed to ORY-2001 as a promising CNS epigenetic drug able to target neuroinflammatory and neurodegenerative diseases and provided preclinical support for the subsequent design of early-stage clinical trials.

3.
ACS Pharmacol Transl Sci ; 4(6): 1818-1834, 2021 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-34927013

RESUMO

Lysine-specific demethylase 1 (LSD1 or KDM1A) is a chromatin modifying enzyme playing a key role in the cell cycle and cell differentiation and proliferation through the demethylation of histones and nonhistone substrates. In addition to its enzymatic activity, LSD1 plays a fundamental scaffolding role as part of transcription silencing complexes such as rest co-repressor (CoREST) and nucleosome remodeling and deacetylase (NuRD). A host of classical amine oxidase inhibitors such as tranylcypromine, pargyline, and phenelzine together with LSD1 tool compounds such as SP-2509 and GSK-LSD1 have been extensively utilized in LSD1 mechanistic cancer studies. Additionally, several optimized new chemical entities have reached clinical trials in oncology such as ORY-1001 (iadademstat), GSK2879552, SP-2577 (seclidemstat), IMG-7289 (bomedemstat), INCB059872, and CC-90011 (pulrodemstat). Despite this, no single study exists that characterizes them all under the same experimental conditions, preventing a clear interpretation of published results. Herein, we characterize the whole LSD1 small molecule compound class as inhibitors of LSD1 catalytic activity, disruptors of SNAIL/GFI1 (SNAG)-scaffolding protein-protein interactions, inducers of cell differentiation, and potential anticancer treatments for hematological and solid tumors to yield an updated, unified perspective of this field. Our results highlight significant differences in potency and selectivity among the clinical compounds with iadademstat being the most potent and reveal that most of the tool compounds have very low activity and selectivity, suggesting some conclusions derived from their use should be taken with caution.

4.
CNS Drugs ; 35(3): 331-344, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33755924

RESUMO

BACKGROUND: Vafidemstat, an inhibitor of the histone lysine-specific demethylase KDM1A, corrects cognition deficits and behavior alterations in rodent models. Here, we report the results from the first-in-human trial of vafidemstat in healthy young and older adult volunteers. A total of 110 volunteers participated: 87 were treated with vafidemstat and 23 with placebo. OBJECTIVES: The study aimed to determine the safety and tolerability of vafidemstat, to characterize its pharmacokinetic and pharmacodynamic profiles, to assess its central nervous system (CNS) exposure, and to acquire the necessary data to select the appropriate doses for long-term treatment of patients with CNS disease in phase II trials. METHODS: This single-center, randomized, double-blind, placebo-controlled phase I trial included a single and 5-day repeated dose-escalation and open-label CNS penetration substudy. Primary outcomes were safety and tolerability; secondary outcomes included analysis of the pharmacokinetics and pharmacodynamics, including chemoprobe-based immune analysis of KDM1A target engagement (TE) in peripheral blood mononuclear cells (PBMCs) and platelet monoamine oxidase B (MAOB) inhibition. CNS and cognitive function were also evaluated. RESULTS: No severe adverse events (AEs) were reported in the dose-escalation stage. AEs were reported at all dose levels; none were dose dependent, and no significant differences were observed between active treatment and placebo. Biochemistry, urinalysis, vital signs, electrocardiogram, and hematology did not change significantly with dose escalation, with the exception of a transient reduction of platelet counts in an extra dose level incorporated for that purpose. Vafidemstat exhibits rapid oral absorption, approximate dose-proportional exposures, and moderate systemic accumulation after 5 days of treatment. The cerebrospinal fluid-to-plasma unbound ratio demonstrated CNS penetration. Vafidemstat bound KDM1A in PBMCs in a dose-dependent manner. No MAOB inhibition was detected. Vafidemstat did not affect the CNS or cognitive function. CONCLUSIONS: Vafidemstat displayed good safety and tolerability. This phase I trial confirmed KDM1A TE and CNS penetration and permitted characterization of platelet dynamics and selection of phase IIa doses. TRIAL REGISTRATION: EUDRACT No. 2015-003721-33, filed 30 October 2015.


Assuntos
Histona Desmetilases/antagonistas & inibidores , Oxidiazóis/farmacocinética , Oxidiazóis/uso terapêutico , Área Sob a Curva , Sistema Nervoso Central/efeitos dos fármacos , Método Duplo-Cego , Feminino , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Masculino , Inibidores da Monoaminoxidase/farmacocinética , Inibidores da Monoaminoxidase/farmacologia
5.
J Clin Oncol ; 38(36): 4260-4273, 2020 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-33052756

RESUMO

PURPOSE: Iadademstat is a novel, highly potent, and selective inhibitor of LSD1 (KDM1A), with preclinical in vitro and in vivo antileukemic activity. This study aimed to determine safety and tolerability of iadademstat as monotherapy in patients with relapsed/refractory acute myeloid leukemia (R/R AML). METHODS: This phase I, nonrandomized, open-label, dose-escalation (DE), and extension-cohort (EC) trial included patients with R/R AML and evaluated the safety, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary antileukemic activity of this orally bioavailable first-in-class lysine-specific demethylase 1 inhibitor. RESULTS: Twenty-seven patients were treated with iadademstat on days 1 to 5 (5-220 µg/m2/d) of each week in 28-day cycles in a DE phase that resulted in a recommended dose of 140 µg/m2/d of iadademstat as a single agent. This dose was chosen to treat all patients (n = 14) in an EC enriched with patients with MLL/KMT2A-rearranged AML. Most adverse events (AEs) were as expected in R/R AML and included myelosuppression and nonhematologic AEs, such as infections, asthenia, mucositis, and diarrhea. PK data demonstrated a dose-dependent increase in plasma exposure, and PD data confirmed a potent time- and exposure-dependent induction of differentiation biomarkers. Reductions in blood and bone marrow blast percentages were observed, together with induction of blast cell differentiation, in particular, in patients with MLL translocations. One complete remission with incomplete count recovery was observed in the DE arm. CONCLUSION: Iadademstat exhibits a good safety profile together with signs of clinical and biologic activity as a single agent in patients with R/R AML. A phase II trial of iadademstat in combination with azacitidine is ongoing (EudraCT No.: 2018-000482-36).


Assuntos
Inibidores Enzimáticos/uso terapêutico , Histona Desmetilases/antagonistas & inibidores , Leucemia Mieloide Aguda/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Inibidores Enzimáticos/farmacologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva
6.
Cancer Cell ; 33(3): 495-511.e12, 2018 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-29502954

RESUMO

The lysine-specific demethylase KDM1A is a key regulator of stem cell potential in acute myeloid leukemia (AML). ORY-1001 is a highly potent and selective KDM1A inhibitor that induces H3K4me2 accumulation on KDM1A target genes, blast differentiation, and reduction of leukemic stem cell capacity in AML. ORY-1001 exhibits potent synergy with standard-of-care drugs and selective epigenetic inhibitors, reduces growth of an AML xenograft model, and extends survival in a mouse PDX (patient-derived xenograft) model of T cell acute leukemia. Surrogate pharmacodynamic biomarkers developed based on expression changes in leukemia cell lines were translated to samples from patients treated with ORY-1001. ORY-1001 is a selective KDM1A inhibitor in clinical trials and is currently being evaluated in patients with leukemia and solid tumors.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Histona Desmetilases/efeitos dos fármacos , Leucemia Mieloide Aguda/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Modelos Animais de Doenças , Histona Desmetilases/antagonistas & inibidores , Histona Desmetilases/genética , Humanos , Leucemia Mieloide Aguda/genética , Camundongos , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo
7.
Curr Opin Pharmacol ; 23: 52-60, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26057211

RESUMO

The covalent modification of histones is closely associated with regulation of gene transcription. Chromatin modifications have been suggested to represent an epigenetic code that is dynamically 'written' and 'erased' by specialized proteins, and 'read', or interpreted, by proteins that translate the code into gene expression changes. Initially thought to be an irreversible process, histone methylation is now known to be reversed by demethylases, FAD dependent amineoxidases and by iron(II)-alpha-ketoglutarate dependent deoxygenases of the Jumonji family. Altered histone demethylase activities have been associated with human disease, including cancer. The first wave of novel investigational drugs directed against KDM1A has recently entered the clinic, and the first specific inhibitor targeting a Jumonji KDM is advancing in preclinical regulatory studies.


Assuntos
Benzoatos/administração & dosagem , Ciclopropanos/administração & dosagem , Histona Desmetilases/antagonistas & inibidores , Animais , Benzoatos/química , Ciclopropanos/química , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/química , Histona Desmetilases/química , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia
8.
Epigenomics ; 7(4): 609-26, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26111032

RESUMO

Histone methylation and demethylation are important processes associated with the regulation of gene transcription, and alterations in histone methylation status have been linked to a large number of human diseases. Initially thought to be an irreversible process, histone methylation is now known to be reversed by two families of proteins containing over 30 members that act to remove methyl groups from specific lysine residues present in the tails of histone H3 and histone H4. A rapidly growing number of reports have implicated the FAD-dependent lysine specific demethylase (KDM1) family in cancer, and several small-molecule inhibitors are in development for the treatment of cancer. An additional role has emerged for KDM1 in brain function, offering additional opportunities for the development of novel therapeutic strategies in neurodegenerative disease. A decade after the identification of KDM1A as a histone demethylase, the first selective inhibitors have now reached the clinic.


Assuntos
Epigênese Genética , Histona Desmetilases/genética , Neoplasias/genética , Doenças Neurodegenerativas/genética , Sequência de Aminoácidos , Animais , Terapia Genética , Histona Desmetilases/química , Histona Desmetilases/metabolismo , Humanos , Dados de Sequência Molecular , Neoplasias/terapia , Doenças Neurodegenerativas/terapia
9.
J Neuropathol Exp Neurol ; 63(10): 1003-14, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15535128

RESUMO

DNA microarray technology is based on the principle of hybridization between 2 complementary strands of nucleic acids, one being fixed into a solid membrane, the other being the sample to analyze. This has resulted in a very powerful method to examine differential gene expression between samples, and has been widely used in the study of tumors. The application of DNA microarray technology to the study of the nervous system has to consider several properties of the nervous tissue: composition of various neuronal types, as well as astrocytes, oligodendrocytes, and microglia; regional and area differences; developmental and age-dependent variations; and functional and pathological status. Moreover, human samples are usually obtained postmortem following variable agonal periods and postmortem delays between death and tissue preservation, which are accompanied by variable RNA degradation. Yet human postmortem nervous tissue stored in brain banks offers a unique opportunity to facilitate material for the study of diseases of the nervous system and to gain direct understanding on the mechanisms of disease. This review analyzes the application of DNA microarray technology to current practice using brain-banked tissues in order to recognize and minimize sub-optimal processing of brain samples and to correct pitfalls due to inadequate procedures. Also discussed are RNA preservation and RNA degradation effects on expression pattern assessments, analysis of individual versus pooled samples, array normalization, types of DNA chip platforms, whole genomic analysis versus specialized chips, and microgenomics. Minimizing RNA degradation and improving detection of resistant RNA in postmortem brain has been considered in detail in order to improve the efficiency and reliability of DNA microarray technology employed in the study of human postmortem nervous tissue.


Assuntos
Encéfalo/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , RNA/metabolismo , Bancos de Tecidos , Animais , Cadáver , Genômica , Humanos , Hipóxia/metabolismo , Neurobiologia
10.
Neurobiol Dis ; 22(2): 265-73, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16380264

RESUMO

Parkinson disease (PD) and dementia with Lewy bodies (DLB) are characterized by the accumulation of abnormal alpha-synuclein and ubiquitin in protein aggregates conforming Lewy bodies and Lewy neurites. Ubiquitin C-terminal hydrolase-1 (UCHL-1) disassembles polyubiquitin chains to increase the availability of free monomeric ubiquitin to the ubiquitin proteasome system (UPS) thus favoring protein degradation. Since mutations in the UCHL-1 gene, reducing UPS activity by 50%, have been reported in autosomal dominant PD, and UCHL-1 inhibition results in the formation of alpha-synuclein aggregates in mesencephalic cultured neurons, the present study was initiated to test UCHL-1 mRNA and protein levels in post-mortem frontal cortex (area 8) of PD and DLB cases, compared with age-matched controls. TaqMan PCR assays, and Western blots demonstrated down-regulation of UCHL-1 mRNA and UCHL-1 protein in the cerebral cortex in DLB (either in pure forms, not associated with Alzheimer disease: AD, and in common forms, with accompanying AD changes), but not in PD, when compared with age-matched controls. Interestingly, UCHL-1 mRNA and protein expressions were reduced in the medulla oblongata in the same PD cases. Moreover, UCHL-1 protein was decreased in the substantia nigra in cases with Lewy body pathology. UCHL-1 down-regulation was not associated with reduced protein levels of several proteasomal subunits, including 20SX, 20SY, 19S and 11Salpha. Yet UCHL-3 expression was reduced in the cerebral cortex of PD and DLB patients. Together, these observations show reduced UCHL-1 expression as a contributory factor in the abnormal protein aggregation in DLB, and points UCHL-1 as a putative therapeutic target in the treatment of DLB.


Assuntos
Encéfalo/enzimologia , Regulação para Baixo/fisiologia , Doença por Corpos de Lewy/enzimologia , Neurônios/enzimologia , Ubiquitina Tiolesterase/metabolismo , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/enzimologia , Doença de Alzheimer/genética , Doença de Alzheimer/fisiopatologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Córtex Cerebral/enzimologia , Córtex Cerebral/patologia , Córtex Cerebral/fisiopatologia , Feminino , Humanos , Corpos de Lewy/enzimologia , Corpos de Lewy/genética , Doença por Corpos de Lewy/genética , Doença por Corpos de Lewy/fisiopatologia , Masculino , Bulbo/enzimologia , Bulbo/patologia , Bulbo/fisiopatologia , Pessoa de Meia-Idade , Neurônios/patologia , Doença de Parkinson/enzimologia , Doença de Parkinson/genética , Doença de Parkinson/fisiopatologia , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , RNA Mensageiro/metabolismo , Transdução de Sinais/fisiologia , Substância Negra/enzimologia , Substância Negra/patologia , Substância Negra/fisiopatologia , Ubiquitina/metabolismo , Ubiquitina Tiolesterase/genética
11.
Mol Cell Neurosci ; 28(4): 599-612, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15797708

RESUMO

The development of the nervous system (NS) requires the coordinated migration of multiple waves of neurons and subsequent processes of neurite maturation, both involving selective guidance mechanisms. In Caenorhabditis elegans, unc-53 codes for a new multidomain protein involved in the directional migration of a subset of cells. We describe here the first functional characterization of the mouse homologue, mouse Neuron navigator 1 (mNAV1), whose expression is largely restricted to the NS during development. EGFP-mNAV1 associates with microtubules (MTs) plus ends present in the growth cone through a new microtubule-binding (MTB) domain. Moreover, its overexpression in transfected cells leads to MT bundling. The abolition of mNAV1 causes loss of directionality in the leading processes of pontine-migrating cells, providing evidence for a role of mNAV1 in mediating Netrin-1-induced directional migration.


Assuntos
Movimento Celular/fisiologia , Proteínas Associadas aos Microtúbulos/fisiologia , Fatores de Crescimento Neural/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Neurônios/fisiologia , Animais , Células COS , Células Cultivadas , Chlorocebus aethiops , Desenvolvimento Fetal/fisiologia , Humanos , Camundongos , Proteínas Associadas aos Microtúbulos/biossíntese , Proteínas Associadas aos Microtúbulos/genética , Fatores de Crescimento Neural/biossíntese , Fatores de Crescimento Neural/genética , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Neurônios/química
12.
Genomics ; 80(1): 21-30, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12079279

RESUMO

We have cloned the gene neuron navigator-1 (NAV1), a human homolog of unc-53, a gene involved in axon guidance in Caenorhabditis elegans. Duplications during evolution gave rise to three human homologs located on chromosomes 1q32.1, 11p15.1, and 12q21.1. NAV1 and NAV2 are expressed in the developing brain. NAV1, NAV2, and NAV3 expression is detected in adult heart, kidney, and brain, respectively. NAV1 encodes a protein lacking, in the aminoterminal part, a CH domain present in the other NAV genes. The first exon of NAV1 arose through an ancient internal duplication of sequences that also gave rise to exon 8 of NAV3 and exon 7 of NAV2. A detailed study of the NAV environment on the different chromosomes reveals incomplete micro-syntheny between the three regions. Through analysis of the phylogenetic relationships for three different gene families in the NAV environment, we reconstructed part of the events that formed these regions.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Proteínas dos Microfilamentos/genética , Fatores de Crescimento Neural/genética , Proteínas do Tecido Nervoso/genética , Processamento Alternativo , Sequência de Aminoácidos , Animais , Northern Blotting , DNA Helicases , Drosophila/genética , Evolução Molecular , Humanos , Proteínas Associadas aos Microtúbulos , Dados de Sequência Molecular , Família Multigênica , Especificidade de Órgãos , Filogenia , Alinhamento de Sequência , Sintenia
13.
Mol Reprod Dev ; 68(2): 232-9, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15095345

RESUMO

In this article we study the proteins responsible for chromatin condensation during spermiogenesis in the cephalopod Octopus vulgaris. The DNA of ripe sperm nuclei in this species is condensed by a set of five different proteins. Four of these proteins are protamines. The main protamine (Po2), a protein of 44 amino acid residues, is extraordinarily simple (composed of only three different amino acid types: arginine (R), serine (S), and glycine (G). It is a basic molecule consisting of 79.5 mol% arginine residues. The rest of the protamines (Po3, Po4, Po5) are smaller molecules (33, 28, and 30 amino acid residues, respectively) that are homologous among themselves and probably with the main Po2 protamine. The ripe sperm nucleus of O. vulgaris also contains a small quantity of a molecule (Po1) that is similar to Po2 protamine. This protein could represent a Po2 protamine-precursor in a very advanced step of its processing. We discuss the characteristics of these proteins, as well as the relation between the complexity of chromatin condensation and the transitions of nuclear proteins during spermiogenesis in O. vulgaris.


Assuntos
Cromatina/fisiologia , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Octopodiformes/fisiologia , Espermatogênese/fisiologia , Sequência de Aminoácidos , Animais , Núcleo Celular/metabolismo , Dados de Sequência Molecular , Proteínas Nucleares/metabolismo , Protaminas/metabolismo
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