Functional analysis of ARF1 from Cymbidium goeringii in IAA response during leaf development.

Background: Cymbidium is an economically important genus of flowering orchids cultivated in China because of showing graceful leaf shapes and elegant flower coloration. However, the deterioration of the ecological environment and the difficulty of conservation management have become increasing challenges for maintaining its germplasm resources. ARFs are critical transcription factors in the auxin signaling pathway and have been found to play pivotal roles in leaf growth and development in previous studies. However, their functions and mechanisms in Cymbidium goeringii remain to be clarified. Methods: The sequence of the CgARF1 gene was analyzed by bioinformatics. The expression of this gene in different tissues and under IAA treatment was detected by quantitative real-time PCR analysis. The CgARF1 gene was overexpressed in wild-type Arabidopsis and Nicotiana benthamiana via the Agrobacterium infection method. Acetone-ethanol solvent extraction was applied for the determination of chlorophyll contents, and the contents of endogenous hormones were determined using the enzyme-linked immunosorbent assay technique. Results: CgARF1 cloned from C. goeringii 'Songmei' was 2,049 bp in length and encoded 682 amino acids containing three typical domains: a B3 DNA binding domain, an Aux_resp domain and an AUX/IXX family domain. The expression pattern of CgARF1 in different tissues of C. goeringii showed that its expression was highest in the leaves and changed greatly under IAA treatment. Subcellular localization studies showed that the protein was mainly localized in the cell nucleus. CgARF1-overexpressing lines exhibited leaf senescence and a decreased chlorophyll content. Under IAA treatment, CgARF1 regulates the rooting length, rooting number and rooting rate from detached leaves. The levels of endogenous hormones in transgenic leaves were also significantly changed. Conclusion: These results indicated that CgARF1 overexpression is responsive to IAA treatment during leaf development. This study provides a foundation for future research on the function of the ARF gene family in C. goeringii.

Tumors exploit FTO-mediated regulation of glycolytic metabolism to evade immune surveillance.

The ever-increasing understanding of the complexity of factors and regulatory layers that contribute to immune evasion facilitates the development of immunotherapies. However, the diversity of malignant tumors limits many known mechanisms in specific genetic and epigenetic contexts, manifesting the need to discover general driver genes. Here, we have identified the m6A demethylase FTO as an essential epitranscriptomic regulator utilized by tumors to escape immune surveillance through regulation of glycolytic metabolism. We show that FTO-mediated m6A demethylation in tumor cells elevates the transcription factors c-Jun, JunB, and C/EBPß, which allows the rewiring of glycolytic metabolism. Fto knockdown impairs the glycolytic activity of tumor cells, which restores the function of CD8+ T cells, thereby inhibiting tumor growth. Furthermore, we developed a small-molecule compound, Dac51, that can inhibit the activity of FTO, block FTO-mediated immune evasion, and synergize with checkpoint blockade for better tumor control, suggesting reprogramming RNA epitranscriptome as a potential strategy for immunotherapy.

Alternative treatments of genetic distances for species delimitation in Callosciurinae and Sciurinae (Rodentia: Sciuridae).

There are many DNA taxonomy methods available, but single-locus data coupled with distance-based analyses still dominate species identification in practice. Genetic distance thresholds are often used for assigning genetic diversity into entities corresponding to species but are criticized for non-universality or arbitrary. This study investigated an alternative approach for determining genetic thresholds that used iteratively sister-clade clustering for sister species boundary detection within a phylogenetic framework. This method was separately applied to two close subfamilies of Callosciurinae and Sciurinae in Rodentia using the cyt b gene. Our results showed that genetic thresholds for Callosciurinae and Sciurinae were 4.0% and 6.0%, respectively, indicating that the optimized thresholds could be lineage-specific. The use of these thresholds for taxa partitioning yielded a very similar putative species number as the prevailing ABGD method, and increased species diversity by 74.2% and 20.7% in Callosciurinae and Sciurinae, respectively. This suggested that additional cryptic species were present that warrant further investigation. We further tested the performance limitation of our method by simulating the impacts of tree construction and sampling limitation. The results showed that it preformed equally well for different trees but failed to work when inter- or intraspecific sampling is insufficient. These findings support the feasibility of this approach as an alternative tool for species delineation when only single-locus information is available for large datasets.