Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print Genetic 'tag team' keeps cells on cycle

Genetic 'tag team' keeps cells on cycle

May 08, 2008

DURHAM, N.C. -- By surveying the activity of thousands of genes at several different time points, researchers at the Duke Institute for Genome Sciences & Policy have uncovered new evidence that a network of influential genes act as a kind of genetic tag team to orchestrate one of the most fundamental aspects of all life: the cell cycle.

"A cell doesn't want to divide before it is finished copying its DNA or it will end up with broken chromosomes," a failure with potentially devastating consequences, said Steven Haase, an assistant professor of biology at Duke and member of the IGSP.




He added that although the new insights into the cell cycle were made in single-celled yeast, they may well apply to human cells. "Essentially everything that works in yeast has its functional analog in mammalian cells," Haase said.

He and his colleagues at the IGSP's Center for Systems Biology reported their findings in an advanced online publication of the journal Nature on May 7, 2008. The work was supported by the American Cancer Society, the Alfred P. Sloan Foundation, the National Science Foundation and the National Institutes of Health.

Scientists thought they had already identified all of the major players in keeping cells on track. Earlier studies of small numbers of genes indicated that the carefully timed program of cell growth and division was governed by a handful of genes aptly known as cyclins, along with their partners, the CDKs. (The scientists who first identified these genes received a Nobel Prize for their discovery in 2001).

To see how significant a role cyclins actually have, the Duke team took a look at the bigger picture --an ability only recently made possible by advances in genome technologies, Haase noted.

"It's a new way of thinking," he said. "We've spent decades on a reductionist approach to science" -- in which researchers typically knock out one or two genes to see what they do. "That method has been phenomenally successful. But now, with genome technologies, we have the opportunity to look at the dynamics of all the genes at the same time."

In this case, they evaluated the activity of about 6,000 genes over time in mutant yeast cells that lacked functional cyclins.

Under the old models, the parade of gene activity should have come to an abrupt halt without cyclin. Instead, while the yeast cells outwardly showed signs of the disruption and stopped dividing, nearly 70 percent of the periodic genes within them continued to turn on and off right on schedule.

The result doesn't mean that cyclins aren't important, Haase said, but there is certainly more to the story.

Haase's team now thinks that many cell cycle activities are driven by a series of transcription factors (genes that switch other genes on and off), acting one after another. Transcription factor one turns on the genes under its control along with transcription factor two; transcription factor two turns on its set of genes plus transcription factor three, and so on. The last transcription factors in the series then go back to turn on the first, starting the whole cycle over again.

Mathematical models constructed by the team showed that the waves of activity driven by such a network could provide a "very robust oscillator" even without cyclins, Haase said.

In fact, cyclins themselves are among the genes targeted by this transcription-activating tag team. Those cyclins are also known to influence the behavior of the transcription factors in the network. Therefore, Haase suggests that precise control over the cell cycle is ultimately achieved through the joint effort of the transcription factor network and cyclins. In other words, the two keep each other in line, which explains how cell division usually manages to persevere over a wide range of conditions.

"When the cell cycle fails, one of the most devastating outcomes is cancer," he said. "Obviously, if this layer of control functions in mammalian cells, we'd like to know about it."

Duke University



Related Cell Cycle Current Events and Cell Cycle News Articles Cell Cycle Current Events and Cell Cycle News RSS Cell Cycle Current Events and Cell Cycle News RSS
Checkered history of mother and daughter cells explains cell cycle differences
When mother and daughter cells are created each time a cell divides, they are not exactly alike. They have the same set of genes, but differ in the way they regulate them.

Protein interaction network can respond Helicobacter pylori infection?
Helicobacter pylori (H pylori) is a gram negative bacterium which infects about 50% of the world population. H pylori colonization causes a strong systemic immune response.

Promising novel treatment for human cancer -- Chrysanthemum indicum extract
A series of studies have demonstrated that Chrysanthemum indicum possesses antimicrobial, antiinflammatory, immunomodulatory, and neuroprotective effects.

Chemotherapy resistance: Checkpoint protein provides armor against cancer drugs
Cell cycle checkpoints act like molecular tripwires for damaged cells, forcing them to pause and take stock.

Study supports DNA repair-blocker research in cancer therapy
Scientists at Dana-Farber Cancer Institute have uncovered the mechanism behind a promising new approach to cancer treatment: damaging cancer cells' DNA with potent drugs while simultaneously preventing the cells from repairing themselves.

Researchers develop new, more-sensitive assay for detecting DNA methylation in colon cancer
A study published in this week's online issue of Nature Biotechnology, demonstrates a unique and highly sensitive method for detecting methylation-associated cancers.

Math model accurately mimics cell division in carbon-cycling bacterium
Scientists from the Department of Biological Sciences and the Virginia Bioinformatics Institute (VBI) at Virginia Tech have developed a quantitative, mathematical model of DNA replication and cell division for the bacterium Caulobacter crescentus.

Pitt researchers find promising candidate protein for cancer prevention vaccines
Researchers at the University of Pittsburgh School of Medicine have learned that some healthy people naturally developed an immune response against a protein that is made in excess levels in many cancers, including breast, lung, and head and neck cancers.

EphA2-targeted therapy delivers chemo directly to ovarian cancer cells
With a novel therapeutic delivery system, a research team led by scientists at The University of Texas M. D. Anderson Cancer Center has successfully targeted a protein that is over-expressed in ovarian cancer cells.

Scientists track impact of DNA damage in the developing brain
Switching off a key DNA repair system in the developing nervous system is linked to smaller brain size as well as problems in brain structures vital to movement, memory and emotion.
More Cell Cycle Current Events and Cell Cycle News Articles
The Cell Cycle: Principles of Control (Primers in Biology) (Primers in Biology)

The Cell Cycle: Principles of Control (Primers in Biology) (Primers in Biology)
by David O. Morgan (Author)

The Cell Cycle is an account of the mechanisms that control cell division, beginning with a description of the phases and main events of the cell cycle and the main model organisms in cell-cycle analysis, including Xenopus, Drosophila, and yeasts. Later chapters focus on the molecules and mechanisms of the cell-cycle control system, including the cyclin-dependent kinase family of protein kinases, the cyclins that activate them, and the signaling molecules that regulate them, and discuss cell-cycle control in development and the failure of controls in cancer.

The Cell Cycle: An Introduction

The Cell Cycle: An Introduction
by Andrew Murray (Author), Tim Hunt (Author)

In the last decade there has been a revolution in our comprehension of how cells grow and divide. Results from experiments on yeast, embryos, and cultured mammalian cells have unified seemingly disparate viewpoints into a single set of principles for normal cellular reproduction in plants, animals and bacteria. Written by two leading participants in that revolution, The Cell Cycle provides the first thorough, authoritative account of the new philosophy of normal cellular reproduction and how it emerged. It is a vivid portrayal of the molecular logic of the cell: how the cell engine induces DNA replication and chromosome replication; how the integrity of genetic information is preserved; and how cell size and environmental signals regulate the cycle of growth and division. By...

  Cell Cycle
by Landes Bioscience % Jesse

Multidisciplinary journal covering most fields of biology and medicine including basic and cancer cell cycles, signal transduction, molecular and cell biology, apoptosis, senescence, cell functions in norm and disease, development, and evolution.

Odyssey Battery PC625: Battery, Dry Cell, 12 V, Deep Cycle, 265 Cold Cranking Amps, Top Post, Each

Odyssey Battery PC625: Battery, Dry Cell, 12 V, Deep Cycle, 265 Cold Cranking Amps, Top Post, Each
by Odyssey Battery



Blitz Cycle - Muscle Cell Pump Amplifier - Bottle of 200

Blitz Cycle - Muscle Cell Pump Amplifier - Bottle of 200
by Fizogen

Blitz Cycle Muscle Cell Pump Amplifier EXPLODE YOUR PUMPS and BLAST YOUR MUSCLE CELLS with the most powerful combination of performance enhancing compounds to date! The first ever arginine, citrulline and creatine esters combined with the anabolic salts of orotic acid and a natural acetate ester of pure 20-beta-hydroxy-ecdysone extract. Subject of 3 pending U.S. patents, BLITZ CYCLE combines the latest advancements in muscle signaling compounds that may dramatically increase vascularity, workload capacity, power output, cellular expansion, gene expression, receptor stimulation, endurance and energy levels. The multiple mechanisms of action employed are combined to stimulate accelerated recovery and repair of muscle fiber, which may cause a dramatic expansion and thickening of the myocytic...

Cell Division 1: Mitosis & the Cell Cycle

Cell Division 1: Mitosis & the Cell Cycle
by iKnow

Use the power of 3-D animation to excite your students about cell division! They will learn the phases of mitosis in animal and plant cells, and the difference between mitosis and cytokinesis. Students can compare and contrast the phases of mitosis in side-by-side plant and animal cell micrographs. Video microscopy makes mitosis come alive in an amphibian lung cell and a zebrafish embryo. The eukaryotic cell cycle is presented in detail in 6 fully narrated animations. Topics covered include: DNA replication and structure, cell cycle variations, molecular control of a cell's progress through the cell cycle, and a discussion of cancer. Students will explore the anatomy of plant, animal, and bacteria cells with interactive diagrams and definitions. Prokaryotic cell division is compared to...

MK Deep Cycle Gel Cell 12 Volt Battery for Backup Sump Pumps

MK Deep Cycle Gel Cell 12 Volt Battery for Backup Sump Pumps
by MK Battery

Our best battery for use in Marine situations and particularly strong for use in the Backup Sump Pump industry. This design will out-last even the best Marine Deep Cycle batteries. For the power you need WHEN you need it, this is the one to buy. It holds its charge longer and can handle the demands of the best back up sump pumps. Whether using direct 12 Volt back-up systems, or connecting through a power inverter, this battery has the reserve capacity to keep going long after other batteries have quit. When compared to regular deep cycle batteries, this one requires no maintenance and lasts 2-3 times as long. When the others die in 3 years or less, this one lasts 5-10 years with 7-8 years on average.

ICP Solar Cycle Saver Cable #04005

ICP Solar Cycle Saver Cable #04005
by ICP Solar

The ICP Solar cycle saver cable provides a quick and easy connection. This two-foot quick connect wire comes with ring terminals.

Allen Sports Navigator Mobile Phone Software and Bluetooth GPS Device

Allen Sports Navigator Mobile Phone Software and Bluetooth GPS Device
by Allen Bike Racks

Enjoy turn-by-turn driving directions--including visual guidance and voice commands--through your existing mobile phone with the Allen Sports Navigator mobile GPS receiver. In addition to offering all the benefits of an expensive standalone navigation system, the unit continually updates your mapping and point of interest (POI) data over your mobile network (so it's always up to date), and tracks anywhere in the world using Google Earth. The map coverage includes street-level maps of the U.S. and Canada, with additional maps available for purchase. The Power Search database, meanwhile, offers more than 20 million POIs, all available in a single search that includes the Yellow Pages, White Pages, Wcities, and Tele Atlas.

Thanks to the intuitive menu system, you can quickly and...

  Timbuk2 2Way Case (Black, Medium)
by Timbuk2

Attaches to your shoulder strap or belt for easy access to your favorite gadgets. Plush lining protects devices from scratches and elastic side panels insure a snug fit. Velcro top closure secures contents. Designed to fit various gadgets, cameras, and similarly sized digital devices. [Imported]

© 2009 BrightSurf.com