RESUMO
Plant meristem activity depends on accurate execution of transcriptional networks required for establishing optimum functioning of stem cell niches. An Arabidopsis mutant card1-1 (constitutive auxin response with DR5:GFP) that encodes a truncated RPB1 (RNA Polymerase II's largest subunit) with shortened C-terminal domain (CTD) was identified. Phosphorylation of the CTD repeats of RPB1 is coupled to transcription in eukaryotes. Here we uncover that the truncated CTD of RPB1 disturbed cell cycling and enlarged the size of shoot and root meristem. The defects in patterning of root stem cell niche in card1-1 indicates that intact CTD of RPB1 is necessary for fine-tuning the specific expression of genes responsible for cell-fate determination. The gene-edited plants with different CTD length of RPB1, created by CRISPR-CAS9 technology, confirmed that both the full length and the DK-rich tail of RPB1's CTD play roles in the accurate transcription of CYCB1;1 encoding a cell-cycle marker protein in root meristem and hence participate in maintaining root meristem size. Our experiment proves that the intact RPB1 CTD is necessary for stem cell niche maintenance, which is mediated by transcriptional regulation of cell cycling genes.
Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/fisiologia , Ciclo Celular/fisiologia , RNA Polimerases Dirigidas por DNA/fisiologia , Nicho de Células-Tronco/fisiologia , Proteína 9 Associada à CRISPR , Sistemas CRISPR-Cas , Edição de Genes , Regulação da Expressão Gênica de Plantas , Meristema/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Plantas Geneticamente ModificadasAssuntos
Exocitose/fisiologia , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Microscopia de Fluorescência/métodos , Animais , Exocitose/efeitos dos fármacos , Glucose/farmacologia , Secreção de Insulina , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Camundongos , Potássio/farmacologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteína 2 Associada à Membrana da Vesícula/genética , Proteína 2 Associada à Membrana da Vesícula/metabolismoRESUMO
AIM: To investigate the effect of Euphorbia esula (E. esula) extract in inhibiting proliferation and inducing apoptosis in SGC-7901 cells. METHODS: E. esula extract at different concentrations was used to inhibit proliferation and induce apoptosis of human gastric carcinoma SGC-7901 cells. Inhibition of proliferation was detected with thiazolyl blue assay, and apoptosis was detected with fluorescence microscopy, transmission electron microscopy, and flow cytometry. The mechanisms were studied by measurement of caspase-3 and caspase-8 activities and Bax and Bcl2 mRNA expression. RESULTS: The thiazolyl blue assay showed that SGC-7901 cell viability and proliferation were inhibited significantly by E. esula extract in a time- and concentration-dependent manner. Fluorescence microscopy revealed that the cell nuclei showed the characteristic changes of apoptosis, such as uneven staining and chromatin marginalization. Some key features of apoptosis were also observed under transmission electron microscopy, which included cellular shrinkage and the foaming or bubbling phenomenon. When the cells were analyzed by flow cytometry, a sub-G1 peak could be seen clearly. Spectrophotometric assay of caspase-3 and caspase-8 activities in the treated cells showed an approximately two-fold increase. Reverse transcription polymerase chain reaction showed that Bax mRNA expression was upregulated, while Bcl2 mRNA expression was downregulated. CONCLUSION: E. esula extract inhibited proliferation and induced apoptosis in SGC-7901 cells, in a caspase-dependent manner, involving upregulation of Bax and downregulation of Bcl2.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Carcinoma/tratamento farmacológico , Látex/farmacologia , Extratos Vegetais/farmacologia , Neoplasias Gástricas/tratamento farmacológico , Antineoplásicos Fitogênicos/isolamento & purificação , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Carcinoma/genética , Carcinoma/metabolismo , Carcinoma/ultraestrutura , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Euphorbia/química , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Látex/isolamento & purificação , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Fitoterapia , Extratos Vegetais/isolamento & purificação , Plantas Medicinais , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/ultraestrutura , Fatores de TempoRESUMO
OBJECTIVE: To observe the effect of compound of gardenia oil and jujube seed oil learning and memory in ovariectomized rats and its mechanism. METHODS: Animals were randomly divided into six groups: sham group, model group, estrogen group, low dose group, middle dose group and high dose group. The ovariectomized rat models were established by resection of the lateral ovaries. The effect of compound of gardenia oil and jujube seed oil on learning and memory in ovariectomized rats was observed by means of Morris water maze. Acetylcholinesterase (AchE) and nitric oxide synthase (NOS) activities in rat brain were determined. RESULTS: The compound of gardenia oil and jujube seed oil could shorten the incubation period of appearance in castration rats and increase the number passing through Yuan Ping table in ovariectomized rats. As the training time extended, the incubation period of appearance was gradually shortened. The compound of gardenia oil and jujube seed oil could increase NOS activity, and decrease AChE activity in brain of ovariectomized rats. CONCLUSION: The compound of jujube seed oil and gardenia oil could promote the learning and memory in ovariectomized rats. This effect may be related with the increase in activities of NOS, AchE in rat brain.