Other vertebrates such as fish, reptiles, and birds, have red cells that contain nuclei that are inactive. Losing the nucleus enables the red blood cell to contain more oxygen-carrying hemoglobin, thus enabling more oxygen to be transported in the blood and boosting our metabolism.
Scientists have struggled to understand the mechanism by which maturing red blood cells eject their nuclei. Now, researchers in the lab of Whitehead Member Harvey Lodish have modeled the complete process in vitro in mice, reporting their findings in Nature Cell Biology online on February 10, 2008. The first mechanistic study of how a red blood cell loses its nucleus, the research sheds light on one of the most essential steps in mammalian evolution.
It was known that as a mammalian red blood cell nears maturity, a ring of actin filaments contracts and pinches off a segment of the cell that contains the nucleus, a type of “cell division.” The nucleus is then swallowed by macrophages (one of the immune system’s quick-response troops). The genes and signaling pathways that drive the pinching-off process, however, were a mystery.
“Using a cell-culture system we were actually able to watch the cells divide, go through hemoglobin synthesis and then lose their nuclei,” says Lodish, who is also a professor of biology at Massachusetts Institute of Technology. “We discovered that the proteins Rac 1, Rac 2 and mDia2 are involved in building the ring of actin filaments.”
“We were very interested in that Rac 1 and Rac 2 were involved in disposing the nuclei of red blood cells,” says Peng Ji, lead author and postdoctoral researcher in the Lodish lab. “These proteins are known for their role in creating actin fibers in many body cells, and a necessary component of many important cellular functions including cell division that support cell growth.”
His cell-culture system began with red blood cell precursors drawn from an embryonic mouse liver (in mammalian embryos, the liver is the main producer of such cells, rather than bone marrow as in adults). The cultured cells, synchronized to develop together, divided four or five times before losing their nuclei and becoming immature red blood cells. The researchers used simple fluorescence-based assays that enabled them to probe the changes in the red blood cells through the different stages leading up to the loss of the nucleus.
The researchers plan to further investigate the entire process of red blood cell formation, which may lead to insights about genetic alterations that underlie certain red blood cell disorders.
“During normal cell division, each daughter cell receives half the DNA,” comments Lodish. “In this case, when the red blood cell divides, one daughter cell gets all the DNA. What’s fascinating is that in this case, that daughter cell gets eaten by macrophages. Until now, scientists were unable to study these cells because they were unable to see them.”
Cristin Carr | EurekAlert!
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences