Model of a member from the Tex protein family, which is implicated in transcriptional regulation and highly conserved in eukaryotes and prokaryotes. The structure shows significant homology to a human transcription elongation factor that may regulate multiple steps in mRNA synthesis.

Melanoma (skin cancer) cells undergoing programmed cell death, also called apoptosis. This process was triggered by raising the pH of the medium that the cells were growing in. Melanoma in people cannot be treated by raising pH because that would also kill healthy cells. This video was taken using a differential interference contrast (DIC) microscope.

This image shows the extracellular matrix (ECM) on the surface of a soleus (lower calf) muscle in light brown and blood vessels in pink. Near the bottom of the photo, a vessel is opened up to reveal red blood cells. Scientists know less about the ECM in muscle than in other tissues, but it's increasingly clear that the ECM is critical to muscle function, and disruption of the ECM has been associated with many muscle disorders. The ECM in muscles stores and releases growth factors, suggesting that it might play a role in cellular communication.

A typical animal cell cycle lasts roughly 24 hours, but depending on the type of cell, it can vary in length from less than 8 hours to more than a year. Most of the variability occurs in Gap1. Appears in the NIGMS booklet Inside the Cell.

Meiosis is the process whereby a cell reduces its chromosomes from diploid to haploid in creating eggs or sperm. See image 2545 for an unlabeled version of this illustration. See image 2544 for an unlabeled version of this illustration. Featured in The New Genetics.

This 1 1/2-minute video animation was produced for chemical biologist Stuart Schreiber's lab page. The animation shows how diverse chemical structures can be produced in the lab.

These colorful, computer-generated ribbons show the backbone of a molecule that glows a fluorescent red. The molecule, called mStrawberry, was created by chemists based on a protein found in the ruddy lips of a coral. Scientists use the synthetic molecule and other "fruity" ones like it as a dye to mark and study cell structures.

Glucose (top) and sucrose (bottom) are sugars made of carbon, hydrogen, and oxygen atoms. Carbohydrates include simple sugars like these and are the main source of energy for the human body.

During development, a zebrafish embryo is transformed from a ball of cells into a recognizable body plan by sweeping convergence and extension cell movements. This process is called gastrulation. Each line in this video represents the movement of a single zebrafish embryo cell over the course of 3 hours. The video was created using time-lapse confocal microscopy. Related to image 6775.

Cells in an early-stage fruit fly embryo, showing the DIAP1 protein (pink), an inhibitor of apoptosis.

Wound healing requires the action of stem cells. In mice that lack the Sept2/ARTS gene, stem cells involved in wound healing live longer and wounds heal faster and more thoroughly than in normal mice. This confocal microscopy image from a mouse lacking the Sept2/ARTS gene shows a tail wound in the process of healing. See more information in the article in Science.

Related to images 3497 and 3498.

Hippocampal cells in culture with a neuron in green, showing hundreds of the small protrusions known as dendritic spines. The dendrites of other neurons are labeled in blue, and adjacent glial cells are shown in red.

A crystal of Bence Jones protein created for X-ray crystallography, which can reveal detailed, three-dimensional protein structures.

Related to image 5871.

This image shows hundreds of human embryonic stem cells in various stages of differentiating into neurons. Some cells have become neurons (red), while others are still precursors of nerve cells (green). The yellow is an imaging artifact resulting when cells in both stages are on top of each other. Image and caption information courtesy of the California Institute for Regenerative Medicine.

Trypanosoma brucei is a single-cell parasite that causes sleeping sickness in humans. Scientists have been studying trypanosomes for some time because of their negative effects on human and also animal health, especially in sub-Saharan Africa. Moreover, because these organisms evolved on a separate path from those of animals and plants more than a billion years ago, researchers study trypanosomes to find out what traits they may harbor that are common to or different from those of other eukaryotes (i.e., those organisms having a nucleus and mitochondria). This image shows the T. brucei cell membrane in red, the DNA in the nucleus and kinetoplast (a structure unique to protozoans, including trypanosomes, which contains mitochondrial DNA) in blue and nuclear pore complexes (which allow molecules to pass into or out of the nucleus) in green. Scientists have found that the trypanosome nuclear pore complex has a unique mechanism by which it attaches to the nuclear envelope. In addition, the trypanosome nuclear pore complex differs from those of other eukaryotes because its components have a near-complete symmetry, and it lacks almost all of the proteins that in other eukaryotes studied so far are required to assemble the pore.

Serum albumin (SA) is the most abundant protein in the blood plasma of mammals. SA has a characteristic heart-shape structure and is a highly versatile protein. It helps maintain normal water levels in our tissues and carries almost half of all calcium ions in human blood. SA also transports some hormones, nutrients and metals throughout the bloodstream. Despite being very similar to our own SA, those from other animals can cause some mild allergies in people. Therefore, some scientists study SAs from humans and other mammals to learn more about what subtle structural or other differences cause immune responses in the body.

Related to entries 3744 and 3745.

This video shows an instance of abnormal mitosis where chromosomes are late to align. The video demonstrates the spindle checkpoint in action: just one unaligned chromosome can delay anaphase and the completion of mitosis. The cells shown are S3 tissue cultured cells from Xenopus laevis, African clawed frog.

Neutrophil-like cells (blue) in a microfluidic chip preferentially migrating toward LTB4 over fMLP. A neutrophil is a type of white blood cell that is part of the immune system and helps the body fight infection. Both LTB4 and fMLP are molecules involved in immune response. Microfluidic chips are small devices containing microscopic channels, and they are used in a range of applications, from basic research on cells to pathogen detection. The scale bar in this video is 500μm.

A crystal of bovine trypsin protein created for X-ray crystallography, which can reveal detailed, three-dimensional protein structures.

A segment of siRNA, shown in red, guides a "slicer" protein called Argonaute (multi-colored twists and corkscrews) to the target RNA molecules.

A model of the molecule himastatin, which was first isolated from the bacterium Streptomyces himastatinicus. Himastatin shows antibiotic activity. The researchers who created this image developed a new, more concise way to synthesize himastatin so it can be studied more easily.

More information about the research that produced this image can be found in the Science paper “Total synthesis of himastatin” by D’Angelo et al.

Related to image 6850 and video 6851.

X-ray co-crystal structure of Src kinase bound to a DNA-templated macrocycle inhibitor. Related to images 3413, 3414, 3415, 3416, 3417, and 3418.

In 2007, the FDA modified warfarin's label to indicate that genetic makeup may affect patient response to the drug. The widely used blood thinner is sold under the brand name Coumadin®. Scientists involved in the NIH Pharmacogenetics Research Network are investigating whether genetic information can be used to improve optimal dosage prediction for patients.

A white poppy. View cropped image of a poppy here 3423.

The microtubule severing protein, katanin, localizes to chromosomes and regulates anaphase A in mitosis. The movement of chromosomes on the mitotic spindle requires the depolymerization of microtubule ends. The figure shows the mitotic localization of the microtubule severing protein katanin (green) relative to spindle microtubules (red) and kinetochores/chromosomes (blue). Katanin targets to chromosomes during both metaphase (top) and anaphase (bottom) and is responsible for inducing the depolymerization of attached microtubule plus-ends. This image was a finalist in the 2008 Drosophila Image Award.

This crystal structure shows a conserved hypothetical protein from Mycobacterium tuberculosis. Only 12 other proteins share its sequence homology, and none has a known function. This structure indicates the protein may play a role in metabolic pathways. Featured as one of the August 2007 Protein Structure Initiative Structures of the Month.

Crystals of DNase protein created for X-ray crystallography, which can reveal detailed, three-dimensional protein structures.

Nerve cells have long, invisibly thin fibers that carry electrical impulses throughout the body. Some of these fibers extend about 3 feet from the spinal cord to the toes.

This illustration highlights spherical pre-synaptic vesicles that carry the neurotransmitter glutamate. The presynaptic and postsynaptic membranes are shown with proteins relevant for transmitting and modulating the neuronal signal.

PDB 101’s Opioids and Pain Signaling video explains how glutamatergic synapses are involved in the process of pain signaling.

The cerebellum is the brain's locomotion control center. Found at the base of your brain, the cerebellum is a single layer of tissue with deep folds like an accordion. People with damage to this region of the brain often have difficulty with balance, coordination and fine motor skills.

This image of a mouse cerebellum is part of a collection of such images in different colors and at different levels of magnification from the National Center for Microscopy and Imaging Research (NCMIR). Related to image 5800.

As an egg cell develops, a process called polarization controls what parts ultimately become the embryo's head and tail. This picture shows an egg of the fruit fly Drosophila. Red and green mark two types of signaling proteins involved in polarization. Disrupting these signals can scramble the body plan of the embryo, leading to severe developmental disorders.

Time-lapse video of yeast cells undergoing cell division. Nuclear envelopes are shown in green, and spindle pole bodies, which help pull apart copied genetic information, are shown in magenta. This video was captured using wide-field microscopy with deconvolution.

Related to images 6791, 6792, 6793, 6794, 6797, 6798, and video 6796.

The proteasome is a critical multiprotein complex in the cell that breaks down and recycles proteins that have become damaged or are no longer needed. This illustration shows a protein substrate (red) that is bound through its ubiquitin chain (blue) to one of the ubiquitin receptors of the proteasome (Rpn10, yellow). The substrate's flexible engagement region gets engaged by the AAA+ motor of the proteasome (cyan), which initiates mechanical pulling, unfolding and movement of the protein into the proteasome's interior for cleavage into small shorter protein pieces called peptides. During movement of the substrate, its ubiquitin modification gets cleaved off by the deubiquitinase Rpn11 (green), which sits directly above the entrance to the AAA+ motor pore and acts as a gatekeeper to ensure efficient ubiquitin removal, a prerequisite for fast protein breakdown by the 26S proteasome. Related to video 3764.

NIGMS-funded researchers led by Roger Kornberg solved the structure of RNA polymerase II. This is the enzyme in mammalian cells that catalyzes the transcription of DNA into messenger RNA, the molecule that in turn dictates the order of amino acids in proteins. For his work on the mechanisms of mammalian transcription, Kornberg received the Nobel Prize in Chemistry in 2006.

Early on, this Arabidopsis plant embryo picks sides: While one end will form the shoot, the other will take root underground. Short pieces of RNA in the bottom half (blue) make sure that shoot-forming genes are expressed only in the embryo's top half (green), eventually allowing a seedling to emerge with stems and leaves. Like animals, plants follow a carefully orchestrated polarization plan and errors can lead to major developmental defects, such as shoots above and below ground. Because the complex gene networks that coordinate this development in plants and animals share important similarities, studying polarity in Arabidopsis--a model organism--could also help us better understand human development.

Pigment cells are cells that give skin its color. In fishes and amphibians, like frogs and salamanders, pigment cells are responsible for the characteristic skin patterns that help these organisms to blend into their surroundings or attract mates. The pigment cells are derived from neural crest cells, which are cells originating from the neural tube in the early embryo. Investigating pigment cell formation and migration in animals helps answer important fundamental questions about the factors that control pigmentation in the skin of animals, including humans. This image shows a pigment cell from zebrafish at high resolution. Related to images 5755, 5756, 5757 and 5758.

The G switch allows our bodies to respond rapidly to hormones. G proteins act like relay batons to pass messages from circulating hormones into cells. A hormone (red) encounters a receptor (blue) in the membrane of a cell. Next, a G protein (green) becomes activated and makes contact with the receptor to which the hormone is attached. Finally, the G protein passes the hormone's message to the cell by switching on a cell enzyme (purple) that triggers a response. See image 2536 and 2538 for other versions of this image. Featured in Medicines By Design.

During cell division, spindle pole bodies (glowing dots) move toward the ends of yeast cells to separate copied genetic information. Contractile rings (glowing bands) form in cells’ middles and constrict to help them split. This time-lapse video was captured using wide-field microscopy with deconvolution.

Related to images 6791, 6792, 6793, 6794, 6797, 6798, and video 6795.

Gram-negative bacteria perform molecular acrobatics just to eat. Because they're encased by two membranes, they must haul nutrients across both. To test one theory of how the bacteria manage this feat, researchers used computer simulations of two proteins involved in importing vitamin B12. Here, the protein (red) anchored in the inner membrane of bacteria tugs on a much larger protein (green and blue) in the outer membrane. Part of the larger protein unwinds, creating a pore through which the vitamin can pass.

A zebrafish embryo. The blue areas are cell bodies, the green lines are blood vessels, and the red glow is blood. This image was created by stitching together five individual images captured with a hyperspectral multipoint confocal fluorescence microscope that was developed at the Eliceiri Lab.

Ecteinascidin 743 (ET-743, brand name Yondelis), was discovered and isolated from a sea squirt, Ecteinascidia turbinata, by NIGMS grantee Kenneth Rinehart at the University of Illinois. It was synthesized by NIGMS grantees E.J. Corey and later by Samuel Danishefsky. Multiple versions of this structure are available as entries 2790-2797.

A blue laser beam turns on a protein that helps this human cancer cell move. Responding to the stimulus, the protein, called Rac1, first creates ruffles at the edge of the cell. Then it stretches the cell forward, following the light like a horse trotting after a carrot on a stick. This new light-based approach can turn Rac1 (and potentially many other proteins) on and off at exact times and places in living cells. By manipulating a protein that controls movement, the technique also offers a new tool to study embryonic development, nerve regeneration and cancer.

Drugs enter different layers of skin via intramuscular, subcutaneous, or transdermal delivery methods. See image 2531 for an unlabeled version of this illustration. Featured in Medicines By Design.

NIGMS staff are located in the Natcher Building on the NIH campus.

A sensor particle being engulfed by a macrophage—an immune cell—and encapsuled in a compartment called a phagosome. The phagosome then fuses with lysosomes—another type of compartment. The left video shows snowman-shaped sensor particles with fluorescent green nanoparticle “heads” and “bodies” colored red by Förster Resonance Energy Transfer (FRET)-donor fluorophores. The middle video visualizes light blue FRET signals that are only generated when the “snowman” sensor—the FRET-donor—fuses with the lysosomes, which are loaded with FRET-acceptors. The right video combines the other two. The videos were captured using epi-fluorescence microscopy.

More details can be found in the paper “Transport motility of phagosomes on actin and microtubules regulates timing and kinetics of their maturation” by Yu et al.

Featured in the March 15, 2012 issue of Biomedical Beat. Related to Hsp33 Figure 1, image 3354.

A peripheral nerve cell made from human embryonic stem cell-derived neural crest stem cells. The nucleus is shown in blue, and nerve cell proteins peripherin and beta-tubulin (Tuj1) are shown in green and red, respectively. Related to image 3263.

This 2-hour-old fly embryo already has a blueprint for its formation, and the process for following it is so precise that the difference of just a few key molecules can change the plans. Here, blue marks a high concentration of Bicoid, a key signaling protein that directs the formation of the fly's head. It also regulates another important protein, Hunchback (green), that further maps the head and thorax structures and partitions the embryo in half (red is DNA). The yellow dots overlaying the embryo plot the concentration of Bicoid versus Hunchback proteins within each nucleus. The image illustrates the precision with which an embryo interprets and locates its halfway boundary, approaching limits set by simple physical principles. This image was a finalist in the 2008 Drosophila Image Award.

In 2006, scientists developed an optical microscopy technique enabling them to clearly see individual molecules within cells. In 2007, they took the technique, abbreviated STORM, a step further. They identified multicolored probes that let them peer into cells and clearly see multiple cellular components at the same time, such as these microtubules (green) and small hollows called clathrin-coated pits (red). Unlike conventional methods, the multicolor STORM technique produces a crisp and high resolution picture. A sharper view of how cellular components interact will likely help scientists answer some longstanding questions about cell biology.