The Discovery of Plant D-Type Cyclins

Transcriptomic profiling reveals bud dormancy stage dynamics in Japanese cedar (Cryptomeria japonica) throughout the nongrowing period

This study aimed to characterize the vegetative bud status of Japanese cedar (Cryptomeria japonica [L.f.] D. Don) throughout the nongrowing period (October-March). Based on the results of twig experiments and transcriptome analysis, we divided the nongrowing period into four stages. Buds were estimated to form between October and November (stage 1), with bud hardening continuing until December (stage 2). Endodormancy was released and transitioned into ecodormancy in mid-to-late December, with the timing varying by genotype. Buds endured harsh winter conditions during January and February (stage 3) and prepared for subsequent growth in March (stage 4). The number of days to bud burst (DBB) under forcing conditions gradually decreased after the transition to ecodormancy, culminating in bud burst in the field in late April. Transcriptome analysis identified key genes presumed to regulate these stages, such as CONSTANS-like and core clock genes. Furthermore, analysis of three genotypes with differing dormancy characteristics revealed DBB-associated genes, indicating the potential involvement of phytohormone cytokinins in regulating bud burst. Additionally, the PEBP- and SVP-like genes, known for their roles in dormancy regulation in other tree species, exhibited distinct expression patterns in Japanese cedar, highlighting variations in dormancy control mechanisms. This study is the first to categorize bud dormancy stages in conifers during the nongrowing period based on molecular data, and the results provide foundational insights for future investigations into conifer dormancy.

RETINOBLASTOMA-RELATED Has Both Canonical and Noncanonical Regulatory Functions During Thermo-Morphogenic Responses in Arabidopsis Seedlings

Warm temperatures accelerate plant growth, but the underlying molecular mechanism is not fully understood. Here, we show that increasing the temperature from 22°C to 28°C rapidly activates proliferation in the apical shoot and root meristems of wild-type Arabidopsis seedlings. We found that one of the central regulators of cell proliferation, the cell cycle inhibitor RETINOBLASTOMA-RELATED (RBR), is suppressed by warm temperatures. RBR became hyper-phosphorylated at a conserved CYCLIN-DEPENDENT KINASE (CDK) site in young seedlings growing at 28°C, in parallel with the stimulation of the expressions of the regulatory CYCLIN D/A subunits of CDK(s). Interestingly, while under warm temperatures ectopic RBR slowed down the acceleration of cell proliferation, it triggered elongation growth of post-mitotic cells in the hypocotyl. In agreement, the central regulatory genes of thermomorphogenic response, including PIF4 and PIF7, as well as their downstream auxin biosynthetic YUCCA genes (YUC1-2 and YUC8-9) were all up-regulated in the ectopic RBR expressing line but down-regulated in a mutant line with reduced RBR level. We suggest that RBR has both canonical and non-canonical functions under warm temperatures to control proliferative and elongation growth, respectively.

Integrative analysis of physiology, biochemistry and transcriptome reveals the mechanism of leaf size formation in Chinese cabbage (Brassica rapa L. ssp. pekinensis)

Introduction

The leaf, the main product organ, is an essential factor in determining the Chinese cabbage growth, yield and quality.

Methods

To explore the regulatory mechanism of leaf size development of Chinese cabbage, we investigated the leaf size difference between two high-generation inbred lines of Chinese cabbage, Y2 (large leaf) and Y7 (small leaf). Furtherly, the transcriptome and cis-acting elements analyses were conducted.

Results and Discussion

According to our results, Y2 exhibited a higher growth rate than Y7 during the whole growth stage. In addition, the significant higher leaf number was observed in Y2 than in Y7. There was no significant difference in the number of epidermal cells and guard cells per square millimeter between Y2 and Y7 leaves. It indicated that cell numbers caused the difference in leaf size. The measurement of phytohormone content confirmed that GA1 and GA3 mainly play essential roles in the early stage of leaf growth, and IPA and ABA were in the whole leaf growth period in regulating the cell proliferation difference between Y2 and Y7. Transcriptome analysis revealed that cyclins BraA09g010980.3C (CYCB) and BraA10g027420.3C (CYCD) were mainly responsible for the leaf size difference between Y2 and Y7 Chinese cabbage. Further, we revealed that the transcription factors BraA09gMYB47 and BraA06gMYB88 played critical roles in the difference of leaf size between Y2 and Y7 through the regulation of cell proliferation.

Conclusion

This observation not only offers essential insights into understanding the regulation mechanism of leaf development, also provides a promising breeding strategy to improve Chinese cabbage yield.

Effects and mechanisms of GSG2 in esophageal cancer progression

BACKGROUND

Esophageal cancer was recognized as one of the malignant tumors with poor prognosis. Germ cell associated 2 (GSG2) has been reported to be of great significance in cell growth and tumor formation. This study aimed to investigate the biological function and molecular mechanism of GSG2 in esophageal cancer.

METHODS

First, relationship between GSG2 expression and tumor characteristics in esophageal cancer patients was analyzed through immunohistochemical (IHC) staining. MTT assay, flow cytometry, cloning formation assay, wound-healing assay and Transwell assay were used to determine proliferation, apoptosis and migration of esophageal cancer cell with GSG2 knockdown in vitro. Expression of apoptosis related proteins and downstream pathway proteins after GSG2 knockdown were detected through Human Apoptosis Antibody Array and western blot analysis. The GSG2 knockdown function in vivo was explored through a xenograft tumor model.

RESULTS

GSG2 was highly expressed in tumor tissues, which has clinical significance in predicting the malignant degree of patients with esophageal cancer. In addition, GSG2 knockdown significantly inhibited a variety of malignant biological behaviors of esophageal cancer cells, such as inhibiting proliferation, reducing colony formation, promoting apoptosis, hindering migration. The decrease of GSG2 expression in esophageal cancer cells can inhibit the xenograft tumor growth.

CONCLUSIONS

In conclusion, GSG2 was involved in esophageal cancer progression and development, which may provide an effective molecular target for the treatment of esophageal cancer in the future.

Genome-Wide Identification and Analysis of Cell Cycle Genes in Birch

Research Highlights: This study identified the cell cycle genes in birch that likely play important roles during the plant’s growth and development. This analysis provides a basis for understanding the regulatory mechanism of various cell cycles in Betula pendula Roth. Background and Objectives: The cell cycle factors not only influence cell cycles progression together, but also regulate accretion, division, and differentiation of cells, and then regulate growth and development of the plant. In this study, we identified the putative cell cycle genes in the B. pendula genome, based on the annotated cell cycle genes in Arabidopsis thaliana (L.) Heynh. It can be used as a basis for further functional research. Materials and Methods: RNA-seq technology was used to determine the transcription abundance of all cell cycle genes in xylem, roots, leaves, and floral tissues. Results: We identified 59 cell cycle gene models in the genome of B. pendula, with 17 highly expression genes among them. These genes were BpCDKA.1, BpCDKB1.1, BpCDKB2.1, BpCKS1.2, BpCYCB1.1, BpCYCB1.2, BpCYCB2.1, BpCYCD3.1, BpCYCD3.5, BpDEL1, BpDpa2, BpE2Fa, BpE2Fb, BpKRP1, BpKRP2, BpRb1, and BpWEE1. Conclusions: By combining phylogenetic analysis and tissue-specific expression data, we identified 17 core cell cycle genes in the Betulapendula genome.

Overexpression Populus d-Type Cyclin Gene PsnCYCD1;1 Influences Cell Division and Produces Curved Leaf in Arabidopsis thaliana

d-type cyclins (CYCDs) are a special class of cyclins and play extremely important roles in plant growth and development. In the plant kingdom, most of the existing studies on CYCDs have been done on herbaceous plants, with few on perennial woody plants. Here, we identified a Populus d-type cyclin gene, PsnCYCD1;1, which is mainly transcribed in leaf buds and stems. The promoter of PsnCYCD1;1 activated GUS gene expression and transgenic Arabidopsis lines were strongly GUS stained in whole seedlings and mature anthers. Moreover, subcellular localization analysis showed the fluorescence signal of PsnCYCD1;1-GFP fusion protein is present in the nucleus. Furthermore, overexpression of the PsnCYCD1;1 gene in Arabidopsis can promote cell division and lead to small cell generation and cytokinin response, resulting in curved leaves and twisted inflorescence stems. Moreover, the transcriptional levels of endogenous genes, such as ASs, KNATs, EXP10, and PHB, were upregulated by PsnCYCD1;1. Together, our results indicated that PsnCYCD1;1 participates in cell division by cytokinin response, providing new information on controlling plant architecture in woody plants.

Silencing of UAP1L1 inhibits proliferation and induces apoptosis in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is recognized as one of the malignant tumors with poor prognosis. UAP1L1 (UDP-N-acetylglucosamine-1-like-1) affects numerous biological processes, which is a key regulator of the development of malignant tumors. The biological function and molecular mechanism of UAP1L1 in ESCC were explored in this study. The relationship between UAP1L1 and ESCC was analyzed by immunohistochemical staining, revealing the high expression of UAP1L1 in ESCC. Importantly, the increased expression of UAP1L1 indicated the deterioration of patients' condition, which has clinical significance. Furthermore, the loss-of-function assays demonstrated that knockdown of UAP1L1 inhibited the progression of ESCC on suppressing proliferation, hindering migration, and enhancing apoptosis in vitro. Moreover, the apoptosis of ESCC cells was induced by knockdown of UAP1L1 via regulating a variety of apoptosis-related proteins, such as upregulation of Bax, CD40, CD40L, Fas, FasL, IGFBP-6, p21, p27, p53, and SMAC. Additionally, further investigation indicated that UAP1L1 by affecting the PI3K/Akt, CCND1, and MAPK promotes the progression of ESCC. In vivo xenograft model further confirmed that knockdown of UAP1L1 inhibited the development of ESCC. In conclusion, UAP1L1 was involved in the development and progression of ESCC, which may provide a powerful target for future molecular therapies.