Biologists find 'missing link' in the production of protein factories in cells

Jun 22, 2014 by Kim Mcdonald

Biologists at UC San Diego have found the "missing link" in the chemical system that enables animal cells to produce ribosomes—the thousands of protein "factories" contained within each cell that manufacture all of the proteins needed to build tissue and sustain life.

Their discovery, detailed in the June 23 issue of the journal Genes & Development, will not only force a revision of basic textbooks on molecular biology, but also provide scientists with a better understanding of how to limit uncontrolled cell growth, such as cancer, that might be regulated by controlling the output of ribosomes.

Ribosomes are responsible for the production of the wide variety of proteins that include enzymes; structural molecules, such as hair, skin and bones; hormones like insulin; and components of our immune system such as antibodies. Regarded as life's most important molecular machine, ribosomes have been intensively studied by scientists (the 2009 Nobel Prize in Chemistry, for example, was awarded for studies of its structure and function). But until now researchers had not uncovered all of the details of how the proteins that are used to construct ribosomes are themselves produced.

In multicellular animals such as humans, ribosomes are made up of about 80 different proteins (humans have 79 while some other animals have a slightly different number) as well as four different kinds of RNA molecules. In 1969, scientists discovered that the synthesis of the ribosomal RNAs is carried out by specialized systems using two key enzymes: RNA polymerase I and RNA polymerase III. But until now, scientists were unsure if a complementary system was also responsible for the production of the 80 proteins that make up the ribosome.

That's essentially what the UC San Diego researchers headed by Jim Kadonaga, a professor of biology, set out to examine. What they found was the missing link—the specialized system that allows ribosomal proteins themselves to be synthesized by the cell.

"We found that ribosomal proteins are synthesized via a novel regulatory system with the enzyme RNA polymerase II and a factor termed TRF2," Kadonaga says. "For the production of most proteins, RNA polymerase II functions with a factor termed TBP, but for the synthesis of ribosomal proteins, it uses TRF2."

"The discovery of this specialized TRF2-based system for ribosome biogenesis," he adds, "provides a new avenue for the study of and its control of cell growth, and should lead to a better understanding and potential treatment of diseases such as cancer."

Explore further: Protein 'rescues' stuck cellular factories

add to favorites email to friend print save as pdf

Related Stories

Protein 'rescues' stuck cellular factories

Mar 19, 2014

Using a powerful data-crunching technique, Johns Hopkins researchers have sorted out how a protein keeps defective genetic material from gumming up the cellular works. The protein, Dom34, appears to "rescue" protein-making ...

Mimicking living cells: Synthesizing ribosomes

Jun 29, 2013

Synthetic biology researchers at Northwestern University, working with partners at Harvard Medical School, have for the first time synthesized ribosomes—cell structures responsible for generating all proteins and enzymes ...

Team discovers how a protein finds its way

Apr 29, 2013

(Phys.org) —Proteins, the workhorses of the body, can have more than one function, but they often need to be very specific in their action or they create cellular havoc, possibly leading to disease.

Recommended for you

Malaria transmission linked to mosquitoes' sexual biology

17 hours ago

Sexual biology may be the key to uncovering why Anopheles mosquitoes are unique in their ability to transmit malaria to humans, according to researchers at Harvard T. H. Chan School of Public Health and University of Per ...

Intermediary neuron acts as synaptic cloaking device

18 hours ago

Neuroscientists believe that the connectome, a map of each and every connection between the millions of neurons in the brain, will provide a blueprint that will allow them to link brain anatomy to brain function. ...

Skeleton of cells controls cell multiplication

18 hours ago

A research team from Instituto Gulbenkian de Ciencia (IGC; Portugal), led by Florence Janody, in collaboration with Nicolas Tapon from London Research Institute (LRI; UK), discovered that the cell's skeleton ...

New study shows safer methods for stem cell culturing

Feb 25, 2015

A new study led by researchers at The Scripps Research Institute (TSRI) and the University of California (UC), San Diego School of Medicine shows that certain stem cell culture methods are associated with increased DNA mutations. ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.