Cell Biology

Cell division is the process by which a parent cell divides and gives rise to two or more daughter cells. It is a means of reproduction for single-cell organisms. In multicellular organisms, cell division contributes to growth, development, repair, and the generation of reproductive cells (sperms and eggs). Cell division is a tightly regulated process, and aberrant cell division can cause diseases, notably cancer. JoVE's Introduction to Cell Division will cover a brief history of the landmark...

Cell cycle refers to the set of events through which a cell grows, replicates its genome, and ultimately divides into two daughter cells through the process of mitosis. Because the amount of DNA in a cell shows characteristic changes throughout the cycle, techniques known as cell cycle analysis can be used to separate a population of cells according to the different phases of cell cycle they are in, based on their varying DNA content.This video will cover the principles behind cell cycle...

Mitosis is a form of cell division in which a cell’s genetic material is divided equally between two daughter cells. Mitosis can be broken down into six phases, during each of which the cell’s components, such as its chromosomes, show visually distinct characteristics. Advances in fluorescence live cell imaging have allowed scientists to study this process in great detail, providing important insights into the biological control of this process and how it might go wrong in diseases such as...

Cell motility and migration play important roles in both normal biology and in disease. On one hand, migration allows cells to generate complex tissues and organs during development, but on the other hand, the same mechanisms are used by tumor cells to move and spread in a process known as cancer metastasis. One of the primary cellular machineries that make cell movement possible is an intracellular network of myosin and actin molecules, together known as “actomyosin”, which creates a...

Cells migration in response to chemical cues is crucial to development, immunity and disease states such as cancer. To quantify cell migration, a simple assay was developed in 1961 by Dr. Stephen Boyden, which is now known as the transwell migration assay or Boyden chamber assay. This set-up consists an insert which separates the wells of a multiwell plate into top and bottom compartments. Cells whose migration is to be studied are seeded into the top compartment and the chemoattractant...

The extracellular matrix (ECM) is a network of molecules that provide a structural framework for cells and tissues and helps facilitate intercellular communication. Three-dimensional cell culture techniques have been developed to more accurately model this extracellular environment for in vitro study. While many cell processes during migration through 3D matrices are similar to those required for movement across rigid 2D surfaces, including adherence, migration through ECM also requires cells...

Cells can take in substances from the extracellular environment by endocytosis and actively release molecules into it by exocytosis. Such processes involve lipid membrane-bound sacs called vesicles. Knowledge of the molecular architecture and mechanisms of both is key to understanding normal cell physiology, as well as the disease states that arise when they become defective. This video will first briefly review a few pivotal discoveries in the history of endo- and exocytosis research. Next,...

A cell can regulate the amount of particular proteins on its cell membrane through endocytosis, following which cell surface proteins are effectively sequestered in the cytoplasm. Once within a cell, these surface proteins can be either destroyed or “recycled” back to the membrane. The cell surface biotinylation assay provides researchers with a way to study these phenomena. The technique makes use of a derivative of the small molecule biotin, which can label surface proteins and then be...

FM dyes are a class of fluorescent molecules that has found important use in studying the vesicle recycling process. By virtue of a chemical structure, these molecules can insert themselves into the outer leaflet of phospholipid bilayer membranes. After membrane insertion, they are internalized into the cell via endocytosed vesicles, and released when these vesicles recycle back to the membrane. Since, these dyes fluoresce strongly in the hydrophobic environment within membranes and weakly in...

In cells, critical molecules are either built by joining together individual units like amino acids or nucleotides, or broken down into smaller components. Respectively, the reactions responsible for this are referred to as anabolic and catabolic. These reactions require or produce energy typically in the form of a “high-energy” molecule called ATP. Together, these processes make up “Cell Metabolism,” and are hallmarks of healthy, living cells.JoVE’s introduction to cell metabolism briefly...

In fireflies, the luciferase enzyme converts a compound called luciferin into oxyluciferin, and produces light or “luminescence” as a result. This reaction requires energy derived from ATP in order to proceed, so researchers have exploited the luciferase-luciferin interaction to gauge ATP levels in cells. Given ATP’s role as the cell’s currency of energy, the ATP bioluminescence assay can provide insight into cellular metabolism and overall cell health.In this video, JoVE discusses cellular...

Reactive oxygen species are chemically active, oxygen-derived molecules capable of oxidizing other molecules. Because of their reactive nature, there are many deleterious effects associated with unchecked ROS production, including structural damage to DNA and other biological molecules. However, ROS can also be mediators of physiological signaling. There is accumulating evidence that ROS play significant roles in everything from activation of transcription factors to the mediation of...

Necrosis, apoptosis, and autophagic cell death are all manners in which cells can die, and these mechanisms can be induced by different stimuli, such as cell injury, low nutrient levels, or signaling proteins. Whereas necrosis is considered to be an “accidental” or unexpected form of cell death, evidence exists that apoptosis and autophagy are both programmed and “planned” by cells.In this introductory video, JoVE highlights key discoveries pertaining to cell death, including recent work done...

One of the hallmarks of apoptosis is the nuclear DNA fragmentation by nucleases. These enzymes are activated by caspases, the family of proteins that execute the cell death program. TUNEL assay is a method that takes advantage of this feature to detect apoptotic cells. In this assay, an enzyme called terminal deoxynucleotidyl transferase catalyzes the addition of dUTP nucleotides to the free 3’ ends of fragmented DNA. By using dUTPs that are labeled with chemical tags that can produce...

Staining with annexin V and propidium iodide (PI) provides researchers with a way to identify different types of cell death—either necrosis or apoptosis. This technique relies on two components. The first, annexin V, is a protein that binds certain phospholipids called phosphatidylserines, which normally occur only in the inner, cytoplasm-facing leaflet of a cell’s membrane, but become “flipped” to the outer leaflet during the early stages of apoptosis. The second component is the DNA-binding...