Proteins known as transcription factors play a crucial role in gene regulation by activating, enhancing, and even silencing a gene’s expression.  Many textbooks and resources compare transcription factors (TFs) to something like an on/off switch for gene transcription. However, it is a bit more complicated than just turning gene expression on or off. Various properties (e.g. binding affinity, specificity, and genetic variance of binding sites) impact the binding of TFs to DNA, thereby altering gene expression. To study transcription and how it is regulated, scientists study TF-DNA interactions on a genome-wide level. 

Embryonic stem cells (ES cells) are pluripotent stem cells isolated from an inner cell mass of early-stage embryo-blastocysts. ES cells have a high differentiation potential., which means that they have the capacity to develop into whatever cell type the body needs depending on the signals received by the ES cell. At the same time, while ES cells are undifferentiated, they retain the potential to infinitely replicate, making them highly attractive and renewable subjects for targeted cell therapy and regenerative medicine.

Cluster of differentiation, or CD molecules, are cell surface markers that are used for identification of cell types in pathology and other bioscience disciplines. The expression levels of CD markers may increase or decrease (or disappear altogether, at least to undetectable levels) when cells (for example, leukocytes, red blood cells, platelets, and vascular endothelial cells, etc.) differentiate into new and different lineages. Depending on the CD marker, the expression level may identify a phenotype for different segments of cells, such as when they become active or diseased. Most CD molecules are transmembrane proteins or glycoproteins, including extracellular regions that bind a ligand or opposing receptor, transmembrane regions to anchor the CD marker into the cell, and cytoplasmic regions that may confer some adaptor or catalytic function. Some CD molecules can also be "anchored" on the cell membrane by means of inositol phospholipids. A few CD molecules are carbohydrate haptens. The study of CD molecules can be used in many basic immunology research fields, such as the relationship between CD antigen structure and function, cell activation pathway, signal transduction and cell differentiation, etc. It can be used clinically for disease mechanism research, clinical diagnosis, disease prognosis, efficacy tracking and treatment, and more. CD molecules such as CD4, CD8, CD25, etc. can be used to identify populations of cells when studying samples by flow cytometry or immunofluorescence.

The Literature Review

Literature reviews are some of the most widely read and highly cited papers in academia, but writing one can be a daunting task, requiring an expert understanding of the topic at hand. To write a review article is so much more than simply summarizing recent studies published in the field. The most valuable literature reviews, which I find myself going back to again and again, are those that:

The Problem with Cancer Models

Very few cancer drugs succeed in clinical trials, despite showing promise in the lab. Treatments that may work on animal models, cell lines, or even patient-derived xenografts often do not have the same efficacy in patients. The underlying reason is tumor environments within the human body are far more complex than in research models. For example, the tissue structure (histological complexity) and genetic heterogeneity of an animal model is different than that of humans. Even cell lines and patient-derived xenografts, which are human-derived, have their own pitfalls such as genetic mutations and animal-specific tumor evolution, respectively. Due to the inability to reproduce human tumor environments, many drugs fail clinical trials after lengthy and costly development.

The Hippo signal is very conservative in evolution. It regulates organ size and tissue stability by regulating cell proliferation, apoptosis, and stem cell renewal. The core process of Hippo signaling is a kinase tandem process, Mst1/2 and Sav1 form a complex, phosphorylate and activate Lats1/2; Lats1/2 kinase then phosphorylates and inhibits transcriptional coactivators Yap and Taz. Yap and Taz are the most important effectors downstream of the Hippo pathway. Upon dephosphorylation, Yap and Taz translocate to the nucleus and interact with TEAD1-4 or other transcription factors (such as CTGF) to induce gene expression, thereby initiating cell proliferation and inhibiting apoptosis.