MedicineWorld.Org
Your gateway to the world of medicine
Home
News
Cancer News
About Us
Cancer
Health Professionals
Patients and public
Contact Us
Disclaimer

From Medicineworld.org: More Noise In Gene Expression

Cancer main Cancer news Breast cancer  


Do You Read All Of Our Cancer Blogs?

Do You Read All Of Blogs?
Do you read all of the blogs published by medicineworld.org? Many of our bloggers are busy keeping you updated on the various health related topics. We publish the following blogs at this time.

Cancer blog: I manage the cancer blog with lots of help and support form other bloggers. Through this cancer blog my friends and I try to bring stories of hope for patients with cancer. The cancer blog often republishes important blog posts from other cancer related blogs at Medicineworld.org. If you are searching for a blog that covers wide variety of cancer topics, this may be the one for you.

Breast cancer blog: Breast cancer blog is run by Emily and other bloggers and they bring you the latest stories, news and events that are related to breast cancer. Increasing awareness about breast cancer among women and in the general population is the main goal of this breast cancer blog.

Lung cancer blog: Lung cancer blog is managed by Scott with the help of other bloggers. Through this blog Scott and his friends constantly remind the readers about the dangers of smoking. It's a never-ending struggle against this miserable disease with which a social stigma of smoking is associated.

Colon cancer blog: Colon cancer blog is run by Sue and other bloggers. Sue brings a personal touch to the colon cancer blog since her mother died of colon cancer few years ago. She writes about stories, research news and advances in treatment related to colon cancer.

Prostate cancer blog: Prostate cancer is the most common cancer among American men. American Cancer Society estimates that over 230,000 new cases of prostate cancer occur in the United state every year. This important blog about prostate cancer is run by Mark and other bloggers. This blog brings news, stories, and other personal observations related to prostate cancer.

Medicineworld.org publishes a diabetes watch blog and this blog is run by JoAnn other bloggers. This diabetes watch blog brings you the latest in the field of diabetes. This includes personal stories, advances in diagnosis and treatment, and other observations about diabetes. Improving awareness about diabetes is an important mission of this group.

Janet      

More Noise In Gene Expression


More Noise In Gene Expression Jennifer Marciniak and Dmitri Volfson
Human identical twins have different fingerprints and march to the beat of subtly different phenotypes, an indication of heterogeneity which led bioengineering scientists at the University of California, San Diego (UCSD) to devised computer algorithms that identify the underlying sources of variation at the basic level of life: unscripted fluctuations within individual cells and variations between identical cells.

"Researchers might assume that natural selection would prune any sloppiness at the level of gene expression, but recent studies by our group at UCSD and others have shown that is definitely not the case," said Jeff Hasty, a bioengineering professor at UCSD's Jacobs School of Engineering. "A number of individual genes produce less than 10 copies of regulatory messenger molecules, which is such a small number that it makes clockwork-like regularity of downstream cellular circuits statistically impossible. Our group and others have detected and classified significant downstream fluctuations that result from this source of 'intrinsic noise' in gene expression."

Hasty leads a team of scientists at UCSD that will report in a Dec. 21 advanced online publication by Nature a mathematical description of "extrinsic noise," an even larger component of variation in gene expression. This second type of noise results because no two geneticcally identical cells can keep the same time. The measurement of extrinsic noise was based on experiments involving baker's yeast, Saccharomyces cerevisiae, but the phenomenon and the way it is described mathematically would apply to other types of cells and other species.

"Individual yeast cells exist at various stages of their growth cycle, and this extrinsic variability explains a large component of the noise that must be accounted for in creating a mathematical model of the cell," said Dmitri Volfson, project scientist and a co-author of the study. "In this case, one yeast cell may be preparing to divide, another may be the result of a recent division, and the phenotypes of these two otherwise identical cells can be very different."

Macroscopic variations are routinely observed in the genetically identical cells of organisms ranging in complexity from bacteria to mammals. "Watchmakers can neither make individual watches with intrinsically perfect accuracy, nor perfectly synchronize any two watches to eliminate extrinsic variations," said Hasty. "And intrinsic and extrinsic variation in gene expression also prevents genetically identical cells growing side-by-side from ticking in unison."

Intrinsic noise resulting from low copy numbers of molecules has been the focus of earlier studies by Hasty's group. Its Nature paper focuses on extrinsic noise, an even larger source of variation between identical cells growing side-by-side in identical conditions. "This extrinsic noise originates from cells being out of phase in their growth cycle," said Hasty. "It's unavoidable. This study also established an 'extrinsic-noise floor' in 11 genes for which intrinsic noise is negligible."

The group measured the noise floor by used genetically engineered strains of yeast with a green fluorescence marker linked to a gene involved in the metabolism of the sugar galactose. The galactose gene and 10 others were chosen because they are expressed in yeast cells in high copy numbers, a feature that makes intrinsic noise in their expression statistically insignificant. By making cell-to-cell comparisons of the activation of the galactose-fluorescence gene pair in experiments with one to five copies of the gene pair per cell, the team was able to measure the extrinsic-noise floor, a parameter that is needed to create a mathematical algorithm describing gene-expression variation in yeast.

"This may sound relatively straightforward: extrinsic variability is due to individual cells growing out of phase with one another," said Hasty. "However, this study is the first rigorous description of this variability, which will be very helpful to scientists eager to account for variations in gene expression as they build rigorous, comprehensive models of this and other types of cells."

The Nature paper is co-authored by Hasty, Volfson, Ph.D. candidates Jennifer Marciniak and Natalie Ostroff, research scientist Lev S. Tsimring, and Boston University postdoctoral fellow William J. Blake.


Source: Jacobs School of Engineering


Did you know?
Human identical twins have different fingerprints and march to the beat of subtly different phenotypes, an indication of heterogeneity which led bioengineering scientists at the University of California, San Diego (UCSD) to devised computer algorithms that identify the underlying sources of variation at the basic level of life: unscripted fluctuations within individual cells and variations between identical cells.

Medicineworld.org: More Noise In Gene Expression

A look at genes defensive playbook| An alternative to mouse in laboratory| Cell signaling secrets| Charging blood forming stem cells| Clinical research award| Functioning artificial proteins using natures rules| Nano particles to target tumors| Nanotechnology to help with bad hair days| New bio nanotube| Protein serves as motor and steering wheel for regenerating nerves| Translation factor eff1a2 may be an oncoprotein| Tunnel for communication between immune cells| Uncoding the memory code|

Copyright statement
The contents of this web page are protected. Legal action may follow for reproduction of materials without permission.