Science Current Events | Science News | Brightsurf.com
 

Slicing mitotic spindle with lasers, nanosurgeons unravel old pole-to-pole theory

April 27, 2012
The mitotic spindle, an apparatus that segregates chromosomes during cell division, may be more complex than the standard textbook picture suggests, according to researchers at the Harvard School of Engineering and Applied Sciences (SEAS).

The findings, which result from quantitative measurements of the mitotic spindle, will appear tomorrow in the journal Cell.

The researchers used a femtosecond laser to slice through the strands of the organelle and then performed a mathematical analysis to infer the microscopic structure of the spindle from its response to this damage.

"We've been using this nanosurgery technique to understand the architecture and assembly of the spindle in a way that was never possible before," says Eric Mazur, Balkanski Professor of Physics and Applied Physics at Harvard, who co-authored the study. "It's very exciting."

The spindle, which is made of protein strands called microtubules, forms during cell division and segregates chromosomes into the daughter cells. It was previously unclear how microtubules are organized in the spindles of animal cells, and it was often assumed that the microtubules stretch along the length of the entire structure, pole to pole.

Mazur and his colleagues demonstrated that the microtubules can begin to form throughout the spindle. They also vary in length, with the shortest ones close to the poles.

"We wondered whether this size difference might result from a gradient of microtubule stabilization across the spindle, but it actually results from transport," says lead author Jan Brugués, a postdoctoral fellow at SEAS. "The microtubules generally nucleate and grow from the center of the spindle, from which point they are transported towards the poles. They disassemble over the course of their lifespan, resulting in long, young microtubules close to the midline and older, short microtubules closer to the poles."

"This research provides concrete evidence for something that we've only been able to estimate until now," Brugués adds.

Mazur and Brugués worked with Daniel Needleman, Assistant Professor of Applied Physics and Molecular and Cellular Biology at Harvard, and Valeria Nuzzo, a former postdoctoral fellow in Mazur's lab at SEAS, to bring the tools of applied physics to bear on a biological question.

The team used a femtosecond laser to make two small slices perpendicular to the plane of growth of the spindle apparatus in egg extracts of the frog species Xenopus laevis.

They were then able to collect quantitative data on the reconstruction of the spindle following this disruption and precisely determine the length and polarity of individual microtubules. Observing the speed and extent of depolymerization (unraveling) of the spindle, the team worked backwards to compile a complete picture of the beginning and end points of each microtubule. Finally, additional experiments and a numerical model confirmed the role of transport.

"The laser allowed us to make precise cuts and perform experiments that simply were not possible using previous techniques," says Mazur.

With further inquiries into spindle architecture, the researchers hope that scientists will one day have a complete understanding, and possibly even control over, the formation of the spindle.

"Understanding the spindle means understanding cell division," notes Brugués. "With a better understanding of how the spindle is supposed to operate, we have more hope of tackling the range of conditions-from cancer to birth defects-that result from disruptions to the cell cycle or from improper chromosomal segregation."

Harvard University


Related Mitotic Spindle Current Events and Mitotic Spindle News Articles


Studies reveal details of error correction in cell division
Cell biologists led by Thomas Maresca at the University of Massachusetts Amherst, with collaborators elsewhere, report an advance in understanding the workings of an error correction mechanism that helps cells detect and correct mistakes in cell division early enough to prevent chromosome mis-segregation and aneuploidy, that is, having too many or too few chromosomes.

Leicester research team identifies potential new targets for cancer treatments
An international consortium of scientists led by a group from the University of Leicester has announced a new advance in understanding the mechanisms of cancer and how to target it more effectively with new treatments.

Unravelling cell division
At this very moment thousands of our body's cells are duplicating and dividing. This is the mechanism by which the body repairs damaged tissues and regenerates others like skin and hair.

Kinesin-5 structure opens cancer drug targets
The structure of a key part of the machinery that allows cells to divide has been identified by researchers at the University of California, Davis -- opening new possibilities for throwing a wrench in the machine and blocking runaway cell division in cancer.

Split decision: Stem cell signal linked with cancer growth
Researchers at the University of California, San Diego School of Medicine have identified a protein critical to hematopoietic stem cell function and blood formation.

A flip of the mitotic spindle has disastrous consequences for epithelial cells
Constructing a body is like building a house-if you compromise structural integrity, the edifice can collapse.

Molecular forces are key to proper cell division
Studies led by cell biologist Thomas Maresca at the University of Massachusetts Amherst are revealing new details about a molecular surveillance system that helps detect and correct errors in cell division that can lead to cell death or human diseases.

The cell that isn't
This may look like yet another video of a dividing cell, but there's a catch. You are looking at chromosomes (red) being pulled apart by the mitotic spindle (green), but it's not a cell, because there's no cell membrane.

Molecular forces are key to proper cell division
Studies led by cell biologist Thomas Maresca at the University of Massachusetts Amherst are revealing new details about a molecular surveillance system that helps detect and correct errors in cell division that can lead to cell death or human diseases.

The role of the cellular entry point of anthrax identified
Anthrax uses a receptor on the surface of cells to inject its lethal toxins. However, the physiological function of this receptor, named Anthrax Toxin Receptor 2a (Antxr2a), remained unknown until now.
More Mitotic Spindle Current Events and Mitotic Spindle News Articles

5 Steps to a 5 AP Biology 2016

5 Steps to a 5 AP Biology 2016
by Mark Anestis (Author), Kellie Ploeger Cox (Author)


Get ready for your AP Biology exam with this straightforward, easy-to-follow study guide―updated for all the latest exam changes 5 Steps to a 5: AP Biology features an effective, 5-step plan to guide your preparation program and help you build the skills, knowledge, and test-taking confidence you need to succeed. This fully revised edition covers the latest course syllabus and matches the latest exam. The book provides access to McGraw-Hill Education’s interactive AP Planner app, which will enable you to receive a customizable study schedule on your mobile device. Bonus app features daily practice assignment notifications, plus extra practice questions to assess test readiness 2 complete practice AP Biology exams 3 separate study plans to fit your learning...

Cracking the AP Biology Exam, 2016 Edition (College Test Preparation)

Cracking the AP Biology Exam, 2016 Edition (College Test Preparation)
by Princeton Review (Author)


EVERYTHING YOU NEED TO HELP SCORE A PERFECT 5. Equip yourself to ace the AP Biology Exam with The Princeton Review's comprehensive study guide—including 2 full-length practice tests, thorough content reviews, access to our AP Connect online portal, and targeted strategies for every section of the exam.

We don't have to tell you how tough AP Biology is—or how important a stellar score on the AP Exam can be to your chances of getting into a top college of your choice. Written by Princeton Review experts who know their way around Bio, Cracking the AP Biology Exam will give you:

Techniques That Actually Work.
• Tried-and-true strategies to help you avoid traps and beat the test
• Tips for pacing yourself and guessing logically
• Essential tactics to help...

International Review of Cell and Molecular Biology, Volume 313

International Review of Cell and Molecular Biology, Volume 313
by Kwang W. Jeon (Editor)


International Review of Cell and Molecular Biology presents comprehensive reviews and current advances in cell and molecular biology. Articles address structure and control of gene expression, nucleocytoplasmic interactions, control of cell development and differentiation, and cell transformation and growth. The series has a world-wide readership, maintaining a high standard by publishing invited articles on important and timely topics authored by prominent cell and molecular biologists.Authored by some of the foremost scientists in the field Provides comprehensive reviews and current advancesWide range of perspectives on specific subjectsValuable reference material for advanced undergraduates, graduate students and professional scientists...

Kaplan AP Biology 2016 (Kaplan Test Prep)

Kaplan AP Biology 2016 (Kaplan Test Prep)
by Linda Brooke Stabler (Author), Mark Metz (Author), Allison Wilkes M.D. (Author)


The Advanced Placement exam preparation guide that delivers 75 years of proven Kaplan experience and features strategies, practice, and review to help students prep for the AP Biology exam!
Students spend the school year preparing for the AP Biology exam. Now it’s time to reap the rewards: money-saving college credit, advanced placement, or an admissions edge. However, achieving a top score on the AP Biology exam requires more than knowing the material—students need to get comfortable with the test format itself, prepare for pitfalls, and arm themselves with foolproof strategies. That’s where the Kaplan plan has the clear advantage.

Kaplan's AP Biology 2016 contains many essential and unique features to improve test scores, including:
2 full-length practice tests and a...

CliffsNotes AP Biology, Fourth Edition (Cliffs Ap Biology)

CliffsNotes AP Biology, Fourth Edition (Cliffs Ap Biology)
by Phillip E Pack (Author)


Your complete guide to a higher score on the AP Biology exam The bestselling book just got better! CliffsNotes AP Biology gets you ready for test day with a review of the AP Biology exam format and scoring, proven strategies for answering multiple-choice questions, and hints for tackling the essay questions. The practice tests include answers and explanations to help you pinpoint areas for further study, while reviews and exercises address all of the test topics you'll encounter on exam day. Plus, proven test-taking strategies for both the multiple choice and essay parts of the test help you score higher. A new edition to the bestselling AP Biology test prep book on the market Reflects recent changes made to the AP Biology test AP Biology practice tests with complete answers and...

Junqueira's Basic Histology: Text and Atlas, Thirteenth Edition

Junqueira's Basic Histology: Text and Atlas, Thirteenth Edition
by Anthony Mescher (Author)


The histology text the medical field turns to first -- authoritative, concise, beautifully illustrated, and completely up-to-date More than 600 full-color illustrations For more than three decades, Junquiera's Basic Histology has been unmatched in its ability to explain the relationship between cell and tissue structure with their function in the human body. Updated to reflect the latest research in the field and enhanced with more than 600 full-color illustrations, the thirteenh edition of Junqueira's represents the most comprehensive and modern approach to understanding medical histology available anywhere.

Mitotic regulation by NIMA-related kinases

Mitotic regulation by NIMA-related kinases


The NIMA-related kinases represent a family of serine/threonine kinases implicated in cell cycle control. The founding member of this family, the NIMA kinase of Aspergillus nidulans, as well as the fission yeast homologue Fin1, contribute to multiple aspects of mitotic progression including the timing of mitotic entry, chromatin condensation, spindle organization and cytokinesis. Mammals contain a large family of eleven NIMA-related kinases, named Nek1 to Nek11. Of these, there is now substantial evidence that Nek2, Nek6, Nek7 and Nek9 also regulate mitotic events. At least three of these kinases, as well as NIMA and Fin1, have been localized to the microtubule organizing centre of their respective species, namely the centrosome or spindle pole body. Here, they have important functions in...

CliffsNotes Anatomy & Physiology Quick Review, 2ndEdition (Cliffsnotes Quick Review)

CliffsNotes Anatomy & Physiology Quick Review, 2ndEdition (Cliffsnotes Quick Review)
by Steven Bassett (Author)


Inside the Book: Anatomy and Chemistry Basics The Cell Tissues The Integumentary System Bones and Skeletal Tissues The Skeletal System Joints Muscle Tissue The Muscular System Nervous Tissue The Nervous System The Sensory System The Endocrine System The Cardiovascular System The Lymphatic System The Immune System and Other Body Defenses The Respiratory System The Digestive System The Urinary System The Reproductive System Review Questions Resource Center Glossary Index Why CliffsNotes? Access 500 additional practice questions at www.cliffsnotes.com/go/quiz/anatomy_physiology Go with the name you know and trust Get the information you need—fast! CliffsNotes Quick Review books give you a clear, concise, easy-to-use review of the...

Guyton and Hall Textbook of Medical Physiology, 12e

Guyton and Hall Textbook of Medical Physiology, 12e
by John E. Hall (Author)


The twelfth edition of Guyton and Hall Textbook of Medical Physiology continues this best-selling title's long tradition as one of the world's favorite physiology textbooks. The immense success of this book is due to its description of complex physiologic principles in language that is easy to read and understand. Now with an improved color art program, thorough updates reflecting today's medicine and science, and accessible online at Student Consult, this textbook is an excellent source for mastering essential human physiology knowledge. Learn and remember vital concepts easily thanks to short, easy-to-read, masterfully edited chapters and a user-friendly full-color design. See core concepts applied to real-life situations with clinical vignettes throughout the text. Discover the...

Histology: A Text and Atlas: With Correlated Cell and Molecular Biology

Histology: A Text and Atlas: With Correlated Cell and Molecular Biology
by Michael H. Ross PhD (Author), Wojciech Pawlina MD (Author)


Now in its seventh edition, Histology: A Text and Atlas is ideal for medical, dental, health professions, and undergraduate biology and cell biology students. This best-selling combination text and atlas includes a detailed textbook, which emphasizes clinical and functional correlates of histology fully supplemented by vividly informative illustrations and photomicrographs. Separate, superbly illustrated atlas sections follow almost every chapter and feature large-size, full-color digital photomicrographs with labels and accompanied descriptions that highlight structural and functional details of cells, tissues, and organs.
 
Updated throughout to reflect the latest advances in the field, this “two in one” text and atlas features an outstanding art program with all...

© 2015 BrightSurf.com