Navigation Links
Jumping gene helps explain immune system's abilities

A team led by Johns Hopkins scientists has found the first clear evidence that the process behind the human immune system's remarkable ability to recognize and respond to a million different proteins might have originated from a family of genes whose only apparent function is to jump around in genetic material. "Jumping genes" essentially cut themselves out of the genetic material, and scientists have suspected that this ability might have been borrowed by cells needing to build many different proteins from a specific, single set of instructions -- the key to recognizing a million immune-stimulating proteins. But until now, no jumping gene was known to behave just right.

Writing in the Dec. 23 issue of Nature, the researchers show that a jumping gene called Hermes, still active in the common house fly, creates changes in DNA very much like those created by the process behind antigen recognition. "Hermes behaves more like the process used by the immune system to recognize a million different proteins, called antigens, than any previously studied jumping gene," says Nancy Craig, Ph.D., professor of molecular biology and genetics in Johns Hopkins' Institute for Basic Biomedical Sciences and a Howard Hughes Medical Institute investigator. "It provides the first real evidence that the genetic processes behind antigen diversity might have evolved from the activity of a jumping gene, likely a close relative of Hermes." Recognition of so many antigens allows the immune system to fight infection and distinguish friend from foe. The "big picture" behind this ability is that cells build proteins called antibodies that bind to particular antigens, but the early steps of that process have been difficult to study. Hermes should help reveal some secrets of this process, the researchers say. "The immune system takes an approach to protein building similar to that of diners creating a meal at a cafeteria, but how the immun e system's 'a la carte' process happens is still murky," says Craig. But the a la carte approach provides great diversity from a limited number of choices, whether in the immune system or in a cafeteria. For example, at a cafeteria, one diner could have a meal of mashed potatoes, broccoli and a pork chop, and another French fries, salad and a hamburger, and so on through all the possible combinations of offerings. While the choices aren't as tasty, immune cells select sections of certain genetic instructions in order to make instructions for a protein that will recognize a particular antigen. Machinery snips out unwanted genetic sections and reconnects the leftover ones, creating a unique gene (the cellular equivalent of the diner's meal). Snipping out different sections will lead to a different gene, carrying instructions for a different protein that will recognize a different antigen, and on and on. This a la carte process, known as V(D)J recombination, is similar to the excision of jumping genes, but none had matched one of its characteristic oddities: As the unwanted DNA is being removed, the remaining DNA forms a tiny loop. Unexpectedly, when Hermes is being cut out of the DNA, the leftover DNA also forms a hairpin loop, temporarily doubling back on itself, postdoctoral fellows Liqin Zhou, Ph.D., and Rupak Mitra, Ph.D., discovered in experiments in test tubes and with E. coli bacteria. Although this loop distances Hermes from its well-studied cousins, the Hermes protein still has an important family trait, the researchers report. Colleagues at the National Institutes of Health found that a few key building blocks in the protein's DNA-snipping crevice are identical to those in other jumping genes' proteins, even though the overall sequence is quite different. "Because of its similarities both to V(D)J recombination and to other families of jumping genes, Hermes is the first real link between the two processes," says Craig. "It also is likely to be a good model t o figure out what's happening early on in V(D)J recombination." Understanding how Hermes and other jumping genes work also holds clues to fighting bacterial infections, improving gene therapies and tackling disease-carrying insects, Craig notes. Bacterial jumping genes can protect bacteria from certain antibiotics. Scientists also are studying jumping genes as vectors to carry gene therapies and as potential modifiers to disrupt the growth-controlling genes of organisms such as mosquitoes and medflies.
'"/>

Source:John Hopkins Medecine


Related biology news :

1. Jumping genes contribute to the uniqueness of individual brains
2. Jumping gene could provide non-viral alternative for gene therapy
3. Protein helps regulate the genes of embryonic stem cells
4. Scientists reveal the shape of a protein that helps retroviruses break into cells
5. Thai spice helps cut blood sugar swings
6. Chemists synthesize molecule that helps body battle cancers, malaria
7. Ancient DNA helps clarify the origins of two extinct New World horse species
8. Massey Cancer Center researcher helps to identify a piece of the cancer puzzle
9. Study: Well-known protein helps stem cells become secretory cells
10. Beyond genes: Lipid helps cell wall protein fold into proper shape
11. Simple sea sponge helps scientists understand tissue rejection

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/22/2017)... NEW YORK , March 21, 2017 /PRNewswire/ ... Customer Marketing Cloud used by retailers such as ... in its platform — Product Recommendations and Replenishment. Using ... to give more personalized product and replenishment recommendations ... purchases, but also on predictions of customer intent ...
(Date:3/16/2017)... March 16, 2017 CeBIT 2017 - Against identity fraud with DERMALOG ... ... Used combined in one project, multi-biometric solutions provide a crucial contribution ... Used combined in one ... ...
(Date:3/7/2017)... Brandwatch , the leading social intelligence company, today announces that ... uncover insights to support its reporting, help direct future campaigns, and ... youth charity will be using Brandwatch Analytics social listening and analytics ... of the topics and issues that are a priority for its ... "Until recently ...
Breaking Biology News(10 mins):
(Date:3/22/2017)... 22, 2017  UBM and the Massachusetts Medical ... extended partnership and the third annual Massachusetts Medtech Week. ... 21 st Annual MassMEDIC Conference held in ... 3-4, 2017. MassMEDIC will feature ... President and CEO, Scott Whitaker , at ...
(Date:3/22/2017)... York , March 22, 2017 ... largely fragmented, states a research report by Transparency Market ... Pfizer Inc., Amgen Inc., and AbbVie Inc., accounted for ... 2015. The prominent players in this market are focusing ... their product portfolio, which is likely to lead to ...
(Date:3/22/2017)... , March 22, 2017   ... independent provider of product and service solutions ... that it has acquired EPL Archives, Inc., ... customers across the entire regulated product research, ... sample, document storage and ancillary services. EPL ...
(Date:3/22/2017)... Maryland (PRWEB) , ... March 21, 2017 , ... ... Life Science Chief Executive Officer Forum on March 23-24 in San Diego. The ... medical device and diagnostic industries. , Benchworks Vice President Christian Meyer will also ...
Breaking Biology Technology: