An AAGAB-to-CCDC32 handover mechanism controls the assembly of the AP2 adaptor complex.

Vesicular transport relies on multimeric trafficking complexes to capture cargo and drive vesicle budding and fusion. Faithful assembly of the trafficking complexes is essential to their functions but remains largely unexplored. Assembly of AP2 adaptor, a heterotetrameric protein complex regulating clathrin-mediated endocytosis, is assisted by the chaperone AAGAB. Here, we found that AAGAB initiates AP2 assembly by stabilizing its α and σ2 subunits, but the AAGAB:α:σ2 complex cannot recruit additional AP2 subunits. We identified CCDC32 as another chaperone regulating AP2 assembly. CCDC32 recognizes the AAGAB:α:σ2 complex, and its binding leads to the formation of an α:σ2:CCDC32 ternary complex. The α:σ2:CCDC32 complex serves as a template that sequentially recruits the µ2 and ß2 subunits of AP2 to complete AP2 assembly, accompanied by CCDC32 release. The AP2-regulating function of CCDC32 is disrupted by a disease-causing mutation. These findings demonstrate that AP2 is assembled by a handover mechanism switching from AAGAB-based initiation complexes to CCDC32-based template complexes. A similar mechanism may govern the assembly of other trafficking complexes exhibiting the same configuration as AP2.

Understanding the molecular mechanisms of human diseases: the benefits of fission yeasts.

The role of model organisms such as yeasts in life science research is crucial. Although the baker's yeast (Saccharomyces cerevisiae) is the most popular model among yeasts, the contribution of the fission yeasts (Schizosaccharomyces) to life science is also indisputable. Since both types of yeasts share several thousands of common orthologous genes with humans, they provide a simple research platform to investigate many fundamental molecular mechanisms and functions, thereby contributing to the understanding of the background of human diseases. In this review, we would like to highlight the many advantages of fission yeasts over budding yeasts. The usefulness of fission yeasts in virus research is shown as an example, presenting the most important research results related to the Human Immunodeficiency Virus Type 1 (HIV-1) Vpr protein. Besides, the potential role of fission yeasts in the study of prion biology is also discussed. Furthermore, we are keen to promote the uprising model yeast Schizosaccharomyces japonicus, which is a dimorphic species in the fission yeast genus. We propose the hyphal growth of S. japonicus as an unusual opportunity as a model to study the invadopodia of human cancer cells since the two seemingly different cell types can be compared along fundamental features. Here we also collect the latest laboratory protocols and bioinformatics tools for the fission yeasts to highlight the many possibilities available to the research community. In addition, we present several limiting factors that everyone should be aware of when working with yeast models.

Involvement of lipid-translocating exporter family proteins in determination of myriocin sensitivity in budding yeast.

Myriocin is an inhibitor of serine palmitoyltransferase involved in the initial biosynthetic step for sphingolipids, and causes potent growth inhibition in eukaryotic cells. In budding yeast, Rsb1, Rta1, Pug1, and Ylr046c are known as the Lipid-Translocating Exporter (LTE) family and believed to contribute to export of various cytotoxic lipophilic compounds. It was reported that Rsb1 is a transporter responsible for export of intracellularly accumulated long-chain bases, which alleviate the cytotoxicity. In this study, it was found that LTE family genes are involved in determination of myriocin sensitivity in yeast. Analyses of effects of deletion and overexpression of LTE family genes suggested that all LTEs contribute to suppression of cytotoxicity of myriocin. It was confirmed that RSB1 overexpression suppressed reduction in complex sphingolipid levels caused by myriocin treatment, possibly exporting myriocin to outside of the cell. These results suggested that LTE family genes function as a defense mechanism against myriocin.

Prognostic Role of Tumor Budding and Worst Pattern of Invasion in Lymph Node Metastasis and Disease-Free Survival in Oral Squamous Cell Cancer Patients: Result from Central India's Regional Cancer Centre.

Aim: To study the role of pattern of invasion, tumor budding and other clinicopathological parameters in determining the risk of nodal metastases and disease-free survival in oral squamous cell cancer patients. Method: The data of 90 patients with oral squamous cell carcinoma who underwent surgery as their primary modality of treatment were retrospectively analysed. Predictive significance of clinicopathological parameters was assessed with Univariate analysis with Fisher exact test and unpaired t-test. The factors which were significant on Univariate analysis were then analysed with multivariate analysis using logistic regression model to find independent predictors. P value < 0.05 was considered significant. Disease free survival analysis was performed using Kaplan-Meier method and comparison done using the log-rank test for each group. Result: The age of the patients ranged from 22yrs to 72 years with male predominance (81.1%). The most common site of involvement was buccal mucosa. Significant factors predicting nodal metastases on univariate analysis were site (p = 0.031), grade (p = 0.012), T stage (p = < 0.001), Depth of invasion (p = < 0.001), perineural invasion (p = < 0.001), lymphovascular emboli (p = 0.018), tumor budding (p = < 0.001), pattern of invasion (p = < 0.001) and stroma (p = 0.037). On multivariate analysis tumor budding (p = 0.016), depth of invasion (p = 0.016) and perineural invasion (p = 0.044) were predictive of nodal metastasis. A statistically significant difference in 3year disease free survival was seen in infiltrative pattern of invasion and tumor budding which showed a p-value of 0.0372 and 0.0489 respectively. Conclusion: Based on the findings of the present study and review of previous articles tumor budding, worst pattern of invasion, host lymphocyte response should also be included in routine histopathology reporting of OSCC.

Tumour Budding Is a Useful Predictor to Identify High-Risk Stage II Colon Cancer Patients After Curative Surgery.

Aim. Although it is now accepted in the literature that tumour budding (TB) is a useful survival indicator in colon cancer (CC), there are still uncertainties about daily use. Here we methodologically examined the role of TB on survival in CC. Methods. In our study, we examined colon cancer patients who had surgery up to 15 years before presentation. TB was calculated separately using different comprehensive methodological methods. Results. We first investigated an optimal evaluation method. Relationship with prognostic factors was better (Venous invasion [p = .001], advanced pT [p = .003], perineural invasion [p = .040], MSS [p = .016], advanced size [p = .001], tumour obstruction [p = .005], margin involvement [p = .043], and nodal involvement [p = .028]) in Method-1. Similarly, with the same method, the success of the cut-off value, the correlation of TB data (r = .724), and the repeatability of the method (Κappa = .53-.75) were quite good (ROC = .816 [.707-.925]). Then, survival analysis was performed using the best three methods, including this method. In univariate analysis using Method-1, survival analyses were worse in high TB patients (RFS: 81%, p < .001; OS: 84%, p < .001). Multivariate analyses using the same method confirmed that high TB for RFS and OS was an independent poor prognostic parameter for survival (p = .002, Hazard ratio [HR]: 1.42 [1.13-1.80]) and OS (p = .014, HR: 1.38 [1.07-1.79]). Conclusions. With our study, we showed that tumour budding calculated by the standard method is a very valuable prognostic parameter in stage II CC and can contribute to the detection of patients with poor prognosis in stage II CC.

Dynamic Live Cell Imaging of Budding Yeast Meiosis.

For over a century, major advances in understanding meiosis have come from the use of microscopy-based methods. Studies using the budding yeast, Saccharomyces cerevisiae, have made important contributions to our understanding of meiosis because of the facility with which budding yeast can be manipulated as a genetic model organism. In contrast, imaging-based approaches with budding yeast have been constrained by the small size of its chromosomes. The advent of advances in fluorescent chromosome tagging techniques has made it possible to use yeast more effectively for imaging-based approaches as well. This protocol describes live cell imaging methods that can be used to monitor chromosome movements throughout meiosis in living yeast cells.

Fluorescence Microscopy and Immunoblotting for Mitophagy in Budding Yeast.

Selective removal of excess or damaged mitochondria is an evolutionarily conserved process that contributes to mitochondrial quality and quantity control. This catabolic event relies on autophagy, a membrane trafficking system that sequesters cytoplasmic constituents into double membrane-bound autophagosomes and delivers them to lysosomes (vacuoles in yeast) for hydrolytic degradation and is thus termed mitophagy. Dysregulation of mitophagy is associated with various diseases, highlighting its physiological relevance. In budding yeast, the pro-mitophagic single-pass membrane protein Atg32 is upregulated under prolonged respiration or nutrient starvation, anchored on the surface of mitochondria, and activated to recruit the autophagy machinery for the formation of autophagosomes surrounding mitochondria. In this chapter, we provide protocols to assess Atg32-mediated mitophagy using fluorescence microscopy and immunoblotting.

Correlation between tumor budding and the long-term follow-up outcomes after endoscopic submucosal dissection for superficial esophageal squamous cell carcinoma.

BACKGROUND: The effect of tumor budding (TB) on the prognosis of patients with esophageal squamous cell carcinoma (ESCC) after endoscopic submucosal dissection (ESD) remains unclear. We evaluated the long-term outcomes of patients with superficial ESCC after ESD and the risk factors of TB for the long-term prognosis. METHODS: We conducted a retrospective study in a Chinese hospital. All patients with ESCC treated by ESD and reported TB were included consecutively. Comparative analyses were conducted in three parts: specimen analysis, follow-up analyses of unmatched patients, and propensity score-matched (PSM) patients. Cox proportional hazard regression models were constructed to identify risk factors for overall survival and recurrence-free survival (RFS). RESULTS: A total of 437 patients were enrolled [154 TB and 283 no tumor budding (NTB)], and 258 patients (52 TB and 206 NTB) were included in the follow-up analysis. Results showed that the invasion depth, differentiation type, and positive vascular invasion (all p < 0.001) of the TB group were significantly different from the NTB group. The all-cause mortality and the median RFS time between the two groups were comparable. RFS rate at 5 years were 84.6% and 80.6%, respectively (p = 0.43). Cox analyses identified that having other cancers but not TB, as a risk factor independently associated with overall survival and RFS after ESD. CONCLUSION: TB tends to be associated with invasion depth, differentiation type, and positive vascular invasion. However, it might not affect the long-term outcomes of patients with superficial ESCC after ESD when other high-risk factors are negative.

Tumour budding in invasive breast carcinoma of no special type - relationship with clinicopathological parameters.

Each breast cancer is a heterogeneous tumour with different clinicopathological feature, and thus they all have different prognoses. Tumour budding (TB), considered as the first step in tumour metastasis, is the most critical factor for poor prognosis and is associated with the epithelial-mesenchymal transition (EMT). Tumour budding and its clinicopathological features in invasive breast carcinoma of no special type (NST). Patients who underwent surgery for invasive breast carcinoma (NST) between January 2018 and 2022 were retrospectively reviewed from the database, haematoxylin and eosin-stained slides were retrieved and reevaluated. The study included 200 patients. The mean number of TB was 12.8 ±9.6. The number of TB was significantly lower in patients who underwent neoadjuvant chemotherapy treatment ( p = 0.002). There was a weak positive correlation between TB count and tumour size ( r = 0.177). Triple-negative patients had significantly lower TB counts ( p = 0.001). No significant difference was observed between histological grade, nuclear grade, presence of ductal carcinoma in situ , stromal tumour-infiltrating lymphocytes, perineural invasion, lymph node metastasis, and number of TB ( p > 0.05). The number of TB was higher in oestrogen receptor positive tumours ( p = 0.015). There were more TB in patients with angiolymphatic invasion, which supports the pathophysiological relationship between tumour budding, metastasis, and EMT. Clarification of the mechanism of TB with more studies is promising in terms of treatment options.

Ancestral Sequence Reconstruction as a Tool to Detect and Study De Novo Gene Emergence.

New protein-coding genes can evolve from previously noncoding genomic regions through a process known as de novo gene emergence. Evidence suggests that this process has likely occurred throughout evolution and across the tree of life. Yet, confidently identifying de novo emerged genes remains challenging. Ancestral sequence reconstruction is a promising approach for inferring whether a gene has emerged de novo or not, as it allows us to inspect whether a given genomic locus ancestrally harbored protein-coding capacity. However, the use of ancestral sequence reconstruction in the context of de novo emergence is still in its infancy and its capabilities, limitations, and overall potential are largely unknown. Notably, it is difficult to formally evaluate the protein-coding capacity of ancestral sequences, particularly when new gene candidates are short. How well-suited is ancestral sequence reconstruction as a tool for the detection and study of de novo genes? Here, we address this question by designing an ancestral sequence reconstruction workflow incorporating different tools and sets of parameters and by introducing a formal criterion that allows to estimate, within a desired level of confidence, when protein-coding capacity originated at a particular locus. Applying this workflow on ∼2,600 short, annotated budding yeast genes (<1,000 nucleotides), we found that ancestral sequence reconstruction robustly predicts an ancient origin for the most widely conserved genes, which constitute "easy" cases. For less robust cases, we calculated a randomization-based empirical P-value estimating whether the observed conservation between the extant and ancestral reading frame could be attributed to chance. This formal criterion allowed us to pinpoint a branch of origin for most of the less robust cases, identifying 49 genes that can unequivocally be considered de novo originated since the split of the Saccharomyces genus, including 37 Saccharomyces cerevisiae-specific genes. We find that for the remaining equivocal cases we cannot rule out different evolutionary scenarios including rapid evolution, multiple gene losses, or a recent de novo origin. Overall, our findings suggest that ancestral sequence reconstruction is a valuable tool to study de novo gene emergence but should be applied with caution and awareness of its limitations.

An untargeted cultivation approach revealed Pseudogemmatithrix spongiicola gen. nov., sp. nov., and sheds light on the gemmatimonadotal mode of cell division: binary fission.

Members of the phylum Gemmatimonadota can account for up to 10% of the phylogenetic diversity in bacterial communities. However, a detailed investigation of their cell biology and ecological roles is restricted by currently only six characterized species. By combining low-nutrient media, empirically determined inoculation volumes and long incubation times in a 96-well plate cultivation platform, we isolated two strains from a limnic sponge that belong to this under-studied phylum. The characterization suggests that the two closely related strains constitute a novel species of a novel genus, for which we introduce the name Pseudogemmatithrix spongiicola. The here demonstrated isolation of novel members from an under-studied bacterial phylum substantiates that the cultivation platform can provide access to axenic bacterial cultures from various environmental samples. Similar to previously described members of the phylum, the novel isolates form spherical appendages at the cell poles that were believed to be daughter cells resulting from asymmetric cell division by budding. However, time-lapse microscopy experiments and quantitative image analysis showed that the spherical appendages never grew or divided. Although the role of these spherical cells remains enigmatic, our data suggests that cells of the phylum Gemmatimonadota divide via FtsZ-based binary fission with different division plane localization patterns than in other bacterial phyla.

Evidence of 14-3-3 proteins contributing to kinetochore integrity and chromosome congression during mitosis.

The 14-3-3 family of proteins are conserved across eukaryotes and serve myriad important regulatory functions in the cell. Homo- and hetero-dimers of these proteins mainly recognize their ligands via conserved motifs to modulate the localization and functions of those effector ligands. In most of the genetic backgrounds of Saccharomyces cerevisiae, disruption of both 14-3-3 homologs (Bmh1 and Bmh2) are either lethal or cells survive with severe growth defects, including gross chromosomal missegregation and prolonged cell cycle arrest. To elucidate their contributions to chromosome segregation, in this work, we investigated their centromere- and kinetochore-related functions of Bmh1 and Bmh2. Analysis of appropriate deletion mutants shows that Bmh isoforms have cumulative and non-shared isoform-specific contributions in maintaining the proper integrity of the kinetochore ensemble. Consequently, Bmh mutant cells exhibited perturbations in kinetochore-microtubule (KT-MT) dynamics, characterized by kinetochore declustering, mis-localization of kinetochore proteins and Mad2-mediated transient G2/M arrest. These defects also caused an asynchronous chromosome congression in bmh mutants during metaphase. In summary, this report advances the knowledge on contributions of budding yeast 14-3-3 proteins in chromosome segregation by demonstrating their roles in kinetochore integrity and chromosome congression.

Tumor Budding in Invasive Breast Carcinoma, No Special Type: Association With Pathological Prognostic Factors and Comparison of 2 Different Scoring Systems.

Introduction. In contrast to colorectal carcinoma, the significance of tumor budding in breast carcinoma is not established. The X20 objective which is used to assess tumor budding in colorectal carcinoma, is not widely available in countries with limited resources. This study aimed to determine the prevalence of tumor budding and its associations with pathological prognostic factors in invasive breast carcinoma-no special type (IBC-NST), and to assess the correlation between the tumor budding observed using ×20 and ×40 objectives. Methods. A total of 349 excision specimens of IBC-NST were studied. Tumor budding was defined as a single cell/cluster of up to 4 cells at the invasive front and was assessed in hotspots at the advancing edge of the tumor using ×20 and ×40 objectives. Tumor budding was categorized into low (<5/0.785 mm2), intermediate (5-9/0.785 mm2), and high budding (≥10/0.785 mm2) for ×20 objective and low (≤4/0.196 mm2) and high (≥5/0.196 mm2) for ×40 objective based on the number of buds per hotspot. The association between tumor budding and prognostic factors was analyzed with Mann-Whitney U test, Kruskal-Wallis test, χ2 test, and logistic regression. Correlation between tumor budding in ×20 and ×40 objectives was analyzed with Pearson correlation test. Results. The prevalence of tumor budding was 72.5%. There was a significant correlation between the number of buddings observed in ×40 objective and ×20 objective (0.958). High tumor budding observed in both objectives was significantly associated with size (P < .001), lymphovascular invasion (P < .001), perineural invasion (P < .001), lymph node status (P < .001), number of lymph nodes (P < .001), T stage (P < .001), and N stage (P < .001) on univariate analysis, but only lymph node positivity (P < .001) showed significant association on multivariate analysis. Conclusion. Tumor budding assessed with ×20 and ×40 objectives showed a significant correlation and was significantly associated lymph node metastasis on multivariate analysis.

Construction and Characterization of Light-Responsive Transcriptional Systems.

Optogenetic tools provide a means for controlling cellular processes that is rapid, noninvasive, and spatially and temporally precise. With the increase in available optogenetic systems, quantitative comparisons of their performances become important to guide experiments. In this chapter, we first discuss how photoreceptors can be repurposed for light-mediated control of transcription. Then, we provide a detailed protocol for characterizing light-regulated transcriptional systems in budding yeast using fluorescence time-lapse microscopy and mathematical modeling, expanding on our recent publication (Gligorovski et al., Nat Commun 14:3810, 2023).

A Single-step Generation of AlissAID-based Conditional Knockdown Strains Using Nanobody that Targets GFP or mCherry in Budding Yeast.

The Auxin-inducible degron (AID) system is a genetic tool that induces rapid target protein depletion in an auxin-dependent manner. Recently, two advanced AID systems-the super-sensitive AID and AID 2-were developed using an improved pair of synthetic auxins and mutated TIR1 proteins. In these AID systems, a nanomolar concentration of synthetic auxins is sufficient as a degradation inducer for target proteins. However, despite these advancements, AID systems still require the fusion of an AID tag to the target protein for degradation, potentially affecting its function and stability. To address this limitation, we developed an affinity linker-based super-sensitive AID (AlissAID) system using a single peptide antibody known as a nanobody. In this system, the degradation of GFP- or mCherry-tagged target proteins is induced in a synthetic auxin (5-Ad-IAA)-dependent manner. Here, we introduce a simple method for generating AlissAID strains targeting GFP or mCherry fusion proteins in budding yeasts. Key features • AlissAID system enables efficient degradation of the GFP or mCherry fusion proteins in a 5-Ad-IAA-depending manner. • Transforming the pAlissAID plasmids into strains with GFP- or mCherry- tagged proteins.

Immunohistochemical analysis of tumor budding in stage II colon cancer: exploring zero budding as a prognostic marker.

Tumor budding, a biomarker traditionally evaluated using hematoxylin and eosin (H&E) staining, has gained recognition as a prognostic biomarker for stage II colon cancer. Nevertheless, while H&E staining offers valuable insights, its limitations prompt the utilization of pan-cytokeratin immunohistochemistry (IHC). Consequently, this study seeks to evaluate the prognostic significance of tumor budding using IHC in a contemporary cohort of stage II colon cancer patients, aiming to deepen our understanding of this critical facet in cancer prognosis. We conducted a retrospective, population-based cohort study including 493 patients with stage II colon cancer and evaluated tumor budding using IHC, following the H&E-based guidelines proposed by the International Tumor Budding Consensus Conference Group. Correlation between H&E-based and IHC-based tumor budding was assessed using a four-tiered scoring system that included a zero budding (Bd0) category. Survival analyses explored the prognostic significance of tumor budding assessed by IHC and H&E. As expected, IHC-based tumor budding evaluation yielded significantly higher bud counts compared to H&E (p < 0.01). Interestingly, 21 patients were identified with no tumor budding using IHC. This was associated with significantly improved recurrence-free survival (HR = 5.19, p = 0.02) and overall survival (HR = 4.47, p = 0.04) in a multivariate analysis when compared to tumors with budding. The Bd0 category demonstrated a 100% predictive value for the absence of recurrence. In conclusion, IHC-based tumor budding evaluation in stage II colon cancer provides additional prognostic information. The absence of tumor budding is associated with a favorable prognosis and may serve as a potential marker for identifying patients with no risk of recurrence.

Budding and explosive membrane vesicle production by hypervesiculating Escherichia coli strain ΔrodZ.

Escherichia coli produces extracellular vesicles called outer membrane vesicles. In this study, we investigated the mechanism underlying the hypervesiculation of deletion mutant ΔrodZ of E. coli. RodZ forms supramolecular complexes with actin protein MreB and peptidoglycan (PG) synthase, and plays an important role in determining the cell shape. Because mreB is an essential gene, an expression-repressed strain (mreB R3) was constructed using CRISPRi, in which the expression of mreB decreased to 20% of that in the wild-type (WT) strain. In shaken-flask culture, the ΔrodZ strain produced >50 times more vesicles than the WT strain. The mreB-repressed strain mreB R3 showed eightfold higher vesicle production than the WT. ΔrodZ and mreB R3 cells were observed using quick-freeze replica electron microscopy. As reported in previous studies, ΔrodZ cells were spherical (WT cells are rod-shaped). Some ΔrodZ cells (around 7% in total) had aberrant surface structures, such as budding vesicles and dented surfaces, or curved patterns on the surface. Holes in the PG layer and an increased cell volume were observed for ΔrodZ and mreB R3 cells compared with the WT. In conditions of osmotic support using sucrose, the OD660 value of the ΔrodZ strain increased significantly, and vesicle production decreased drastically, compared with those in the absence of sucrose. This study first clarified that vesicle production by the E. coli ΔrodZ strain is promoted by surface budding and a burst of cells that became osmotically sensitive because of their incomplete PG structure.

Multicenter Study on Tumor Budding in Lung Squamous Cell Carcinoma: Comparison Between Biopsy and Resection With Interobserver Variability Assessment.

Grading lung squamous cell carcinoma (LUSC) is controversial and not universally accepted. The histomorphologic feature of tumor budding (TB) is an established independent prognostic factor in colorectal cancer, and its importance is growing in other solid cancers, making it a candidate for inclusion in tumor grading schemes. We aimed to compare TB between preoperative biopsies and resection specimens in pulmonary squamous cell carcinoma and assess interobserver variability. A retrospective cohort of 249 consecutive patients primarily resected with LUSC in Bern (2000-2013, n = 136) and Lausanne (2005-2020, n = 113) with available preoperative biopsies was analyzed for TB and additional histomorphologic parameters, such as spread through airspaces and desmoplasia, by 2 expert pathologists (M.M., C.N.). Results were correlated with clinicopathologic parameters and survival. In resection specimens, peritumoral budding (PTB) score was low (0-4 buds/0.785 mm2) in 47.6%, intermediate (5-9 buds/0.785 mm2) in 27.4%, and high (≥10 buds/0.785 mm2) in 25% of cases (median bud count, 5; IQR, 0-26). Both the absolute number of buds and TB score were similar when comparing tumor edge and intratumoral zone (P = .192) but significantly different from the score obtained in the biopsy (P < .001). Interobserver variability was moderate, regardless of score location (Cohen kappa, 0.59). The discrepant cases were reassessed, and consensus was reached in all cases with identification of causes of discordance. TB score was significantly associated with stage (P = .002), presence of lymph node (P = .033), and distant metastases (P = .020), without significant correlation with overall survival, tumor size, or pleural invasion. Desmoplasia was significantly associated with higher PTB (P < .001). Spread through airspaces was present in 34% and associated with lower PTB (P < .001). To conclude, despite confirming TB as a reproducible factor in LUSC, we disclose areas of scoring ambiguity. Preoperative biopsy evaluation was insufficient in establishing the final TB score of the resected tumor.

Genome-wide analysis of TFIIB's role in termination of transcription.

This study provides evidence that the role of TFIIB extends beyond initiation to include the termination step of transcription. Using GRO-seq analyses, we compared terminator readthrough phenotype in sua7-1 mutant (TFIIB sua7-1 ) and the isogenic wild type (TFIIB WT ) strains. Approximately 74% of genes analyzed exhibited a 2-3-fold increase in readthrough of the poly(A)-termination signal in the TFIIB sua7-1 mutant compared to TFIIB WT cells. Mass spectrometry of affinity purified TFIIB from chromatin fraction found TFIIB exhibiting interaction with CF1A and Rat1 termination complexes in TFIIB WT cells. There was, however, a drastic decrease in TFIIB interaction with CF1A and Rat1 termination complexes in the TFIIB sua7-1 mutant. ChIP assays revealed about 90% decline in recruitment of termination factors in TFIIB sua7-1 mutant compared to wild type cells. The overall conclusion of these results is that TFIIB affects termination of transcription on a genome-wide scale, and TFIIB-termination factor interaction may play a crucial role in the process.

Tumor budding - a potential biomarker in low grade salivary gland carcinomas?

Background: Low-grade salivary gland carcinoma is regularly treated with surgical therapy of the salivary gland without elective neck dissection in T1/2 carcinomas, either alone or with adjuvant radiation therapy. However, occult metastasis and locoregional recurrence influence therapy and outcome. Tumor budding is an emerging prognostic pathological factor in many carcinomas, but has not yet been adequately considered in salivary gland carcinomas. Methods: We conducted a retrospective single-center study of 64 patients diagnosed with low-grade carcinoma of the major salivary glands treated between 2003 and 2017. Pathological risk factors and TNM classification were thoroughly assessed for each case. All hematoxylin and eosin (HE)-stained histological specimens underwent careful examination, and tumor budding was identified following the guidelines set forth by the International Tumor Budding Consensus Conference in 2016. Results: Tumor budding was not statistically significant concerning 5-year survival rate (5-YSR) (p=0.969) and mean overall survival (log-rank p=0.315). Whereas 5-year disease-free survival rate (5-YDFSR) was 87% in the low tumor budding group and 61.1% in the intermediate and high tumor budding group (p=0.021). Mean disease-free survival accounted for 100.2 months (CI: 88.6;111.9) in the low budding score group and 58.7 months (CI: 42.8;74.6) in the other group (log-rank p=0.032). Notably, pT1/2 showed significantly lower tumor buds than pT3/4 stages (2.43 tumor buds/0.785 mm2 vs. 4.19 tumor buds/0.785 mm2, p=0.034). Similar findings were noted comparing nodal-positive and nodal-negative patients, as well as patients with and without lymphovascular invasion and perineural invasion (each p<0.05). Conclusions: Tumor budding might be used as an additional prognostic factor for recurrence in low-grade salivary gland carcinoma, seemingly associated with a higher nodal metastasis rate and advanced tumor stages and a worse 5-YDFSR. Consequently, the evaluation of tumor budding in resection specimens of low-grade salivary gland tumor may prove valuable in decision-making for neck dissection and follow-up strategy.