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Cell Survival: The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.

RNA Splicing

JoVE 10802

The process in which eukaryotic RNA is edited prior to protein translation is called splicing. It removes regions that do not code for proteins and patches the protein-coding regions together. Splicing also allows several protein variants to be expressed from a single gene and plays an essential role in development, tissue differentiation, and adaptation to environmental stress. Errors in splicing can lead to diseases such as cancer. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts designated to become mRNA are called precursor messenger RNA (pre-mRNA). The pre-mRNA is then processed to form mature mRNA that is suitable for protein translation. Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins whereas introns are the non-coding regions. RNA splicing is the process by which introns are removed and exons patched together. Splicing is mediated by the spliceosome—a complex of proteins and RNA called small nuclear ribonucleoproteins (snRNPs). The spliceosome recognizes specific nucleotide sequences at exon/intron boundaries. First, it binds to a GU-containing sequence at the 5’ end of the intron and to a branch point sequence containing an A towards the 3’ end of the intron. In a number of carefully-orches

 Core: Gene Expression

What is Gene Expression?

JoVE 10797

Gene expression is the process in which DNA (i.e., a gene) directs the synthesis of functional products, such as proteins. Cells can regulate gene expression at various stages. It allows organisms to generate different cell types and enables cells to adapt to internal and external factors.

A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is made up of nucleotides and proteins consist of amino acids, a mediator is required to convert the information that is encoded in DNA into proteins. This mediator is the messenger RNA (mRNA). mRNA copies the blueprint from DNA by a process called transcription. In eukaryotes, transcription takes place in the nucleus by complementary base-pairing with the DNA template. The mRNA is then processed and transported into the cytoplasm where it serves as a template for protein synthesis during translation. In prokaryotes, which lack a nucleus, the processes of transcription and translation occur at the same location and almost simultaneously since the newly-formed mRNA is susceptible to rapid degradation. Every cell of an organism contains the same DNA, and consequently the same set of genes. However, not all genes in a cell are “turned on” or use to synthesize proteins. A gene is said to be “expressed” when the protein it encodes is produced by the cel

 Core: Gene Expression

What are Second Messengers?

JoVE 10720

Because many receptor binding ligands are hydrophilic, they do not cross the cell membrane and thus their message must be relayed to a second messenger on the inside. There are several second messenger pathways, each with their own way of relaying information. G-protein coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol path is active when the receptor induces phospholipase C to hydrolyze the phospholipid, phosphatidylinositol biphosphate (PIP2), into two second messengers: diacylglycerol (DAG) and inositol triphosphate (IP3). DAG remains near the cell membrane and activates protein kinase C (PKC). IP3 translocates to the endoplasmic reticulum (ER) and becomes the opening ligand for calcium ion channels on the ER membrane- releasing calcium into the cytoplasm. In the cAMP pathway, the activated receptor induces adenylate cyclase to produce multiple copies of cAMP from nearby adenosine triphosphate (ATP) molecules. cAMP can stimulate protein kinase A (PKA), open calcium ion channels, and initiate the enzyme- Exchange-protein activated by cAMP (Epac). Similar to cAMP, is cyclic guanosine monophosphate (cGMP). cGMP is synthesized from guanosine triphosphate (GTP) molecules when guanylyl cyclase is activated. As a second messenger, cGMP induces protein kinase G

 Core: Cell Signaling

Annexin V and Propidium Iodide Labeling

JoVE 5650

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 Biology

An Introduction to Endocytosis and Exocytosis

JoVE 5646

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…

 Cell Biology

Differential Scanning Calorimetry

JoVE 10487

Source: Danielle N. Beatty and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT


Differential scanning calorimetry (DSC) is an important measurement to characterize thermal properties of materials. DSC is used primarily to calculate the amount of heat stored in a material as it…

 Materials Engineering

Using Differential Scanning Calorimetry to Measure Changes in Enthalpy

JoVE 5559

Source: Laboratory of Dr. Terry Tritt — Clemson University


Differential Scanning Calorimetry (DSC) is a method of thermodynamic analysis based on heat-flux method, wherein a sample material (enclosed in a pan) and an empty reference pan are subjected to identical temperature conditions. The energy difference that is required to…

 General Chemistry

Genomic DNA in Prokaryotes

JoVE 10758

The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the nucleoid. The chromosome is tightly wound, or supercoiled, for efficient storage. Prokaryotes also contain other circular pieces of DNA called plasmids. These plasmids are smaller than the chromosome and often carry genes that confer adaptive functions, such as antibiotic resistance. Although bacterial genomes are much smaller than eukaryotic genomes, they vary considerably in size and gene content. One of the smallest known bacterial genomes is that of Mycoplasma genitalium, a sexually transmitted pathogen that causes urinary and genital tract infections in humans. The M. genitalium genome is 580,076 base pairs long and consists of 559 (476 coding and 83 noncoding) genes. On the other end of the spectrum lies a particular strain of Sorangium cellulosum, a soil-dwelling bacterium. The S. cellulosum genome is enormous for a bacterium at 14,782,125 base pairs long, encoding 11,599 genes. Before the discovery of antibiotics, minor injuries could turn deadly due to the inability to stop simple bacterial infections. The discovery of penicillin in 1928 ushered in the antibiotic era, characterized by revolutionizing medical treatments and an increase in life expectancy. Howe

 Core: Cell Cycle and Division

Primary Cell Culture of Purified GABAergic or Glutamatergic Neurons Established through Fluorescence-activated Cell Sorting

1Institut für Integrative Neuroanatomie, Charité, Universitätsmedizin Berlin, 2Department for Cytometry and Cellsorting, German Rheumatism Research Center, Leibniz Institute, 3Departments of Genetic and Behavioral Neuroscience, Graduate School of Medicine, Gunma University

JoVE 58974

 Neuroscience

Recombinant Collagen I Peptide Microcarriers for Cell Expansion and Their Potential Use As Cell Delivery System in a Bioreactor Model

1Department Tissue Engineering and Regenerative Medicine, University Hospital Wuerzburg, 2Translational Center Regenerative Therapies (TLC-RT), Fraunhofer Institute for Silicate Research ISC, 3Fujifilm Manufacturing Europe B.V.

JoVE 57363

 Bioengineering

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death

1Section of Nephrology, Department of Medicine, University of Illinois at Chicago, 2Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Medical Center, 3Department of Biology, Kutztown University of Pennsylvania, 4Division of Rheumatology, Department of Medicine, Research Institute of the McGill University Health Centre, 5Department of Microbiology & Immunology, University of Illinois at Chicago

JoVE 54980

 Biology

Construction of Defined Human Engineered Cardiac Tissues to Study Mechanisms of Cardiac Cell Therapy

1Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, 2The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, 3Stem Cell & Regenerative Medicine Consortium, LKS Faculty of Medicine, University of Hong Kong

JoVE 53447

 Bioengineering

Fabrication of Extracellular Matrix-derived Foams and Microcarriers as Tissue-specific Cell Culture and Delivery Platforms

1Biomedical Engineering Graduate Program, The University of Western Ontario, 2Department of Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, 3Department of Chemical Engineering, Queen's University, 4Department of Chemical & Biochemical Engineering, Faculty of Engineering, The University of Western Ontario

JoVE 55436

 Bioengineering

Bioprintable Alginate/Gelatin Hydrogel 3D In Vitro Model Systems Induce Cell Spheroid Formation

1Department of Mechanical Engineering, McGill University Montreal, 2Department of Bioengineering, McGill University Montreal, 3Department of Molecular Biology, Instituto Potosino de Investigación Científica y Tecnológica, A.C. (IPICyT), 4Department of Mining and Materials Engineering, McGill University Montreal, 5Department of Biomedical Engineering, McGill University Montreal

JoVE 57826

 Bioengineering

Assessing Tumor Microenvironment of Metastasis Doorway-Mediated Vascular Permeability Associated with Cancer Cell Dissemination using Intravital Imaging and Fixed Tissue Analysis

1Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 2Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, 3Integrated Imaging Program, Albert Einstein College of Medicine, 4Department of Surgery, Montefiore Medical Center, 5Department of Pathology, Montefiore Medical Center

JoVE 59633

 Cancer Research

Isolation of Murine Embryonic Hemogenic Endothelial Cells

1Departments of Medicine, Genetics and Biomedical Engineering, Yale Cardiovascular Research Center, Vascular Biology and Therapeutics Program, Yale Stem Cell Center, Yale University School of Medicine, 2Department of Pediatrics, Section of Neonatal-Perinatal Medicine, Yale University School of Medicine, 3Department of Molecular and Cellular Biology, Baylor College of Medicine

JoVE 54150

 Developmental Biology

Long-term High-Resolution Intravital Microscopy in the Lung with a Vacuum Stabilized Imaging Window

1Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 2Department of Obstetrics/Gynecology and Woman’s Health, Albert Einstein College of Medicine, 3Department of Anatomy & Structural Biology, Albert Einstein College of Medicine, 4Gruss-Lipper Biophotonics Center Integrated Imaging Program, Albert Einstein College of Medicine, 5Medical Research Council Centre for Reproductive Health, Queen’s Medical Research Institute, University of Edinburgh

JoVE 54603

 Cancer Research

Tumorsphere Derivation and Treatment from Primary Tumor Cells Isolated from Mouse Rhabdomyosarcomas

1Graduate School of Biomedical Sciences, Sanford Burnham Prebys Medical Discovery Institute, 2Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, 3Department of Obstetrics, Gynecology, and Reproductive Sciences, Division of Female Pelvic Medicine and Reconstructive Surgery, University California San Diego

JoVE 59897

 Genetics
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