Inteins are naturally occurring intervening sequences that catalyze a protein splicing reaction resulting in intein excision and concatenation of the flanking polypeptides (exteins) with a native peptide bond. Inteins display a diversity of catalytic mechanisms within a highly conserved fold that is shared with hedgehog autoprocessing proteins. The unusual chemistry of inteins has afforded powerful biotechnology tools for controlling enzyme function upon splicing and allowing peptides of different origins to be coupled in a specific, time-defined manner. The extein sequences immediately flanking the intein affect splicing and can be defined as the intein substrate. Because of the enormous potential complexity of all possible flanking sequences, studying intein substrate specificity has been difficult. Therefore, we developed a genetic selection for splicing-dependent kanamycin resistance with no significant bias when six amino acids that immediately flanked the intein insertion site were randomized. We applied this selection to examine the sequence space of residues flanking the Nostoc punctiforme Npu DnaE intein and found that this intein efficiently splices a much wider range of sequences than previously thought, with little N-extein specificity and only two important C-extein positions. The novel selected extein sequences were sufficient to promote splicing in three unrelated proteins, confirming the generalizable nature of the specificity data and defining new potential insertion sites for any target. Kinetic analysis showed splicing rates with the selected exteins that were as fast or faster than the native extein, refuting past assumptions that the naturally selected flanking extein sequences are optimal for splicing.

Protein-protein interactions are crucially important for cellular processes. Knowledge of these interactions improves the understanding of cell cycle, metabolism, signaling, transport, and secretion. Information about interactions can hint at molecular causes of diseases, and can provide clues for new therapeutic approaches. Several (usually expensive and time consuming) experimental methods can probe protein - protein interactions. Data sets, derived from such experiments make the development of prediction methods feasible, and make the creation of protein-protein interaction network predicting tools possible.

Cervical cancer tumors with undetectable HPV (HPV^U) have been underappreciated in clinical decision making. In this study, two independent CC datasets were used to characterize the largest cohort of HPV^U tumors to date (HPV^U = 35, HPV⁺ = 430). Genomic and transcriptome tumor profiles and patient survival outcomes were compared between HPV⁺ and HPV^U tumors. In vitro analyses were done to determine efficacy of the selective CDK4/6 inhibitor palbociclib on HPV^U cancer cell lines. Patients with HPV^U CC tumors had worse progression-free and overall survival outcomes compared to HPV⁺ patients. TP53, ARID1A, PTEN, ARID5B, CTNNB1, CTCF, and CCND1 were identified as significantly mutated genes (SMGs) enriched in HPV^U tumors, with converging functional roles in cell cycle progression. In vitro HPV^U, but not HPV⁺, cancer cell lines with wild type RB1 were sensitive to palbociclib monotherapy. These results indicate that HPV^U status can be translated into the clinic as a predictive biomarker of poor patient response to standard of care treatments. We suggest primary cervix tumors be routinely tested for HPV prior to treatment to identify patients who will benefit from more aggressive precision-driven therapy. Our results identify palbociclib as a lead candidate as an alternative treatment strategy for HPV^U CC patients.

A System Dynamics Model for Improving Primary Education Enrollment in a Developing Country: The system dynamics approach is a holistic way of solving problems in real-time scenarios. This is a powerful methodology and computer simulation modeling technique for framing, analyzing, and discussing complex issues and problems. System dynamics modeling is often the background of a systemic thinking approach and has become a management and organizational development paradigm. This paper proposes a system dynamics approach for studying the importance of infrastructure facilities on the quality of primary education system in a developing nation. The model is built using the Cross Impact Analysis (CIA) method of relating entities and attributes relevant to the primary education system in any given community. The CIA model enables us to predict the effects of infrastructural facilities on the community's access of primary education. This may support policy makers to take more effective actions in campaigns that attempt to improve literacy.

Hemangiosarcoma and angiosarcoma are soft-tissue sarcomas of blood vessel–forming cells in dogs and humans, respectively. These vasoformative sarcomas are aggressive and highly metastatic, with disorganized, irregular blood-filled vascular spaces. Our objective was to define molecular programs which support the niche that enables progression of canine hemangiosarcoma and human angiosarcoma. Dog-in-mouse hemangiosarcoma xenografts recapitulated the vasoformative and highly angiogenic morphology and molecular characteristics of primary tumors. Blood vessels in the tumors were complex and disorganized, and they were lined by both donor and host cells. In a series of xenografts, we observed that the transplanted hemangiosarcoma cells created exuberant myeloid hyperplasia and gave rise to lymphoproliferative tumors of mouse origin. Our functional analyses indicate that hemangiosarcoma cells generate a microenvironment that supports expansion and differentiation of hematopoietic progenitor populations. Furthermore, gene expression profiling data revealed hemangiosarcoma cells expressed a repertoire of hematopoietic cytokines capable of regulating the surrounding stromal cells. We conclude that canine hemangiosarcomas, and possibly human angiosarcomas, maintain molecular properties that provide hematopoietic support and facilitate stromal reactions, suggesting their potential involvement in promoting the growth of hematopoietic tumors. Significance: We demonstrate that hemangiosarcomas regulate molecular programs supporting hematopoietic expansion and differentiation, providing insights into their potential roles in creating a permissive stromal-immune environment for tumor progression.