RESUMO
Bispecific antibodies (BsAbs) are undergoing continued development for applications in oncology and autoimmune diseases. While increasing activity by having more than one targeting arm, most BsAb engineering employs single Fc engagement as monoclonal antibodies. Here, we designed a novel immunoglobulin gamma-1 (IgG1)-derived dual-Fc BsAb containing two Fc regions and two distinct asymmetric antigen binding arms comprising a Fab arm and another VHH domain. In conjunction with the knob-into-hole technology, dual-Fc BsAbs could be produced with a high yield and good stability. We explore how Fc engineering effects on dual-Fc constructs could boost the desired therapeutic efficacy. This new format enabled simultaneous bispecific binding to corresponding antigens. Furthermore, compared to the one-Fc control molecules, dual-Fc BsAbs were shown to increase the avidity-based binding to FcγRs to result in higher ADCC and ADCP activities by potent avidity via binding to two antigens and Fc receptors. Overall, this novel BsAb format with enhanced effector functionalities provides a new option for antibody-based immunotherapy.
Assuntos
Anticorpos Biespecíficos , Anticorpos Biespecíficos/química , Fragmentos Fc das Imunoglobulinas/genética , Anticorpos MonoclonaisRESUMO
Zinc (Zn) deficiency is the most prevalent micronutrient disorder in rice and leads to delayed development and decreased yield. Nevertheless, despite its primary importance, how rice responds to Zn deficiency remains poorly understood. This study presents genetic evidence supporting the crucial role of OsbZIP48 in regulating rice's response to Zn deficiency, consistent with earlier findings in the model plant Arabidopsis. Genetic inactivation of OsbZIP48 in rice seedlings resulted in heightened sensitivity to Zn deficiency and reduced Zn translocation from roots to shoots. Consistently, OsbZIP48 was constitutively expressed in roots, slightly induced by Zn deficiency in shoots and localized into nuclei induced by Zn deficiency. Comparative transcriptome analysis of the wild-type plants and osbzip48 mutant grown under Zn deficiency enabled the identification of OsbZIP48 target genes, including key Zn transporter genes (OsZIP4 and OsZIP8). We demonstrated that OsbZIP48 controlled the expressions of these genes by directly binding to their promoters, specifically to the Zn deficiency response element motif. This study establishes OsbZIP48 as a critical transcription factor in rice's response to Zn deficiency, offering valuable insights for developing Zn-biofortified rice varieties to combat global Zn limitation.
Assuntos
Arabidopsis , Oryza , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Oryza/metabolismo , Zinco/metabolismo , Perfilação da Expressão Gênica , Arabidopsis/genética , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
Cadmium (Cd) is one of the most toxic heavy metal elements in nature, and it causes serious damage to plant cells. Here, we report that a transcription factor OsMYB45 is involved in Cd stress response in rice. OsMYB45 is highly expressed in rice leaves, husks, stamens, pistils, and lateral roots, and its expression is induced by Cd stress. OsMYB45 fused to green fluorescent protein localized to the cell nucleus in onion epidermal cells. Mutation of OsMYB45 resulted in hypersensitivity to Cd treatment, and the concentration of H2O2 in the leaves of mutant nearly doubled, while catalase (CAT) activity was halved compared with the wild-type. Moreover, gene expression analysis indicated that OsCATA and OsCATC expression is significantly lower in the mutant than in the wild-type. In addition, overexpression of OsMYB45 in the mutant complemented the mutant phenotype. Taken together, OsMYB45 plays an important role in tolerance to Cd stress in rice.
Assuntos
Cádmio/toxicidade , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Oryza/genética , Fatores de Transcrição/metabolismo , Catalase/metabolismo , Flores/efeitos dos fármacos , Flores/genética , Flores/fisiologia , Expressão Gênica , Genes Reporter , Peróxido de Hidrogênio/metabolismo , Mutação , Cebolas/efeitos dos fármacos , Cebolas/genética , Cebolas/fisiologia , Especificidade de Órgãos , Oryza/efeitos dos fármacos , Oryza/fisiologia , Fenótipo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/fisiologia , Proteínas Recombinantes de Fusão , Estresse Fisiológico , Fatores de Transcrição/genéticaRESUMO
With the rapid progress of industrialization, the effects of environmental contamination on plant toxicity, and subsequently on human health, is a growing concern. For example, the heavy metal pollution of soil such as that caused by cadmium (Cd) is a serious threat. Therefore, screening for pollution-safe edible plants is an essential approach for growing plants under heavy metal-contaminated soils. In the current study, 35 Chinese cabbage (Brassica pekinensis L.) cultivars were selected with the aim of screening for Cd-safe cultivars (CSCs), analyzing their safety, and exploring the mechanism of Cd accumulation. Our field-culture experiments revealed that the Cd content in the edible parts of the cultivars were varied and were determined to possibly be CSCs. Hydroponics experiments were used to simulate six different degrees of soil contamination (high and low Cd concentrations) on possible CSCs. The results indicated a significant difference (p < 0.05) in Cd concentration in the cultivars, and verified the safety of these possible CSCs. The analyses of the transport coefficient and expression levels showed that the differences in Cd accumulation among the Chinese cabbage cultivars were related to the expression of genes involved in absorption and transport rather than a root-to-shoot translocation limitation.
