Reciprocal regulation of flower induction by ELF3α and ELF3ß generated via alternative promoter usage.

Flowering is critical for sexual reproduction and fruit production. Several pear (Pyrus sp.) varieties produce few flower buds, but the underlying mechanisms are unknown. The circadian clock regulator EARLY FLOWERING3 (ELF3) serves as a scaffold protein in the evening complex that controls flowering. Here, we report that the absence of a 58-bp sequence in the 2nd intron of PbELF3 is genetically associated with the production of fewer flower buds in pear. From rapid amplification of cDNA ends sequencing results, we identified a short, previously unknown transcript from the PbELF3 locus, which we termed PbELF3ß, whose transcript level was significantly lower in pear cultivars that lacked the 58-bp region. The heterologous expression of PbELF3ß in Arabidopsis (Arabidopsis thaliana) accelerated flowering, whereas the heterologous expression of the full-length transcript PbELF3α caused late flowering. Notably, ELF3ß was functionally conserved in other plants. Deletion of the 2nd intron reduced AtELF3ß expression and caused delayed flowering time in Arabidopsis. AtELF3ß physically interacted with AtELF3α, disrupting the formation of the evening complex and consequently releasing its repression of flower induction genes such as GIGANTEA (GI). AtELF3ß had no effect in the absence of AtELF3α, supporting the idea that AtELF3ß promotes flower induction by blocking AtELF3α function. Our findings show that alternative promoter usage at the ELF3 locus allows plants to fine-tune flower induction.

Tough and Antifreezing MXene@Au Hydrogel for Low-Temperature Trimethylamine Gas Sensing.

Trimethylamine (TMA) is one of the important chemical indexes to judge the freshness of marine fish. It is necessary to develop a low temperature TMA sensor to help the monitoring and prediction of the quality of marine fish in cold chain. Herein, a flexible low temperature TMA gas sensor featuring antifreezing and superior mechanical properties was developed based on the Au nanoparticle-modified MXene (MXene@Au) composite. MXene@Au was synthesized and then polymerized with a hydrogel composed of acrylamide (AM), N,N'-methylenebisacrylamide (BIS), sodium carboxymethyl cellulose (CMC), and EG, and the resultant MXene@Au hydrogel was found to exhibit excellent antifreezing performance even at extremely low temperature as well as high tensile strength, ultrastretchability, and toughness, which enabled an efficient gas sensing platform for TMA detection at low temperature. The TMA sensing properties of the flexible MXene@Au DN hydrogel sensor at 25 °C and a low temperature of 0 °C were studied, and a linear relationship between TMA sensitivity and concentration was built. The excellent sensing properties were maintained even under deformation. The application of the MXene@Au DN hydrogel sensor in detection of fish freshness at 0 °C was investigated. The result indicated the potential application of the flexible MXene@Au DN hydrogel gas sensor in dynamic quality monitoring and prediction of marine fish products during its transportation and storage in the cold chain.

MicroRNA profiling in Muc2 knockout mice of colitis-associated cancer model reveals epigenetic alterations during chronic colitis malignant transformation.

Our previous studies have demonstrated that genetic deletion of the Muc2 gene causes colorectal cancers in mice. The current study further showed that at the early stage (<3 months) the Muc2 knockout mice spontaneously developed chronic inflammation in colon and rectum, similar pathological features as human colitis; and at the late stage (>3 months) the mice exhibited colorectal cancer, including a unique phenotype of rectal prolapsed (rectal severe inflammation and adenocarcinoma). Thus, the age of 3 months might be the key point of the transition from chronic inflammation to cancer. To determine the mechanisms of the malignant transformation, we conducted miRNA array on the colonic epithelial cells from the 3-month Muc2-/- and +/+ mice. MicroRNA profiling showed differential expression of miRNAs (i.e. lower or higher expression enrichments) in Muc2-/- mice. 15 of them were validated by quantitative PCR. Based on relevance to cytokine and cancer, 4 miRNAs (miR-138, miR-145, miR-146a, and miR-150) were validate and were found significantly downregulated in human colitis and colorectal cancer tissues. The network of the targets of these miRNAs was characterized, and interestedly, miRNA-associated cytokines were significantly increased in Muc2-/-mice. This is the first to reveal the importance of aberrant expression of miRNAs in dynamically transformation from chronic colitis to colitis-associated cancer. These findings shed light on revealing the mechanisms of chronic colitis malignant transformation.