NPC Progress Meeting 2012 - Netherlands Proteomics Centre

meanings. Two peptides have the same weight when they aremade from exactly the same amino acids, even if the aminoacids are in a different order. We have to cut the peptides intosmaller pieces to identify them; we say we have to ‘fragment’them to help us to see how the amino acids are sorted. For example,we fragment a word and just see some smaller pieces,say ES, T and NO. From the letters in these fragments we canspell the words NOTES or STONE. Let’s have a closer look atthe fragments: we see that E and S are joined together. Thismeans that STONE is not the word we are looking for: NOTESis the only word possible here because the letters E and S arenext to one another in that order!Not in the dictionaryThe neuropeptides are very special peptides. They are likewords that you cannot find in a dictionary; like words thathave a letter from a foreign language. And this is what makesit so difficult to identify them. You have to play around withthe fragments to find the right order of the amino acids.In our research we try to find the right spelling for neuropeptidesthat might play a role in obesity. Once we know whichneuropeptides are in the brain, we try to find out which onesare different in the case of obesity. To do so we look at neuropeptideswe extract from rats. Some rats eat normal food whilea second group gets only fat and sugar. After two weeks the ratsfrom the second group weigh a bit more than the rats that haveeaten normal food, and they are hungrier as well. These ratsare a good model for studying obesity. We hope to find someneuropeptides that we can only see in the fat rats but not inthe rats that get normal food. Perhaps we will also find thatsome neuropeptides in obesity are ‘spelled’ differently.Unravelling the mysteryThe first step in our research is always studying the ABCs ofthe neuropeptides. If we understand how the messengers inour brain are put together, hopefully we can unravel the mysteryof the language of the cells in the brain.Christian Frese (Germany) received his MScdegree from Ruhr University in Bochum in2009. He then moved to Utrecht Universityand joined Albert Heck’s Biomolecular MassSpectrometry and Proteomics Group as aPhD student. He works on the developmentof new peptide fragmentation tools tostudy for example neuropeptides, smallmessengers in the brain, and their role inobesity.Research into flowers: Comparing apples and oranges?Almost everyone associates flowers with certain emotions.For example, on Valentine’s Day they can’t get in enoughred roses, and we associate them with love. And as soonas the first snowdrops and crocuses are out, we feel thatspring has come. All these flowers differ in terms of colour,shape and size, and yet they are all designed in the sameway, with petals, sepals, stamen and a pistil.Suzanne de BruijnHow is it possible that the blueprint for all flowers is the sameand yet the flowers all look so different? In my research I amgoing to investigate that question. The master regulators thatspecify where a petal comes or where a pistil is conservedare the same in each species. However, these regulators turnother genes on or off; which genes those are differ in eachplant. This entire blueprint of regulators and targets is calleda network, and the details of the network are different ineach species. You can compare this to two companies thatboth have the same management yet each produce somethingcompletely different.Changing networksI want to know what changes in a network to form a flower sothat it looks different. To be exact, how does the network thatis controlled by conserved factors change? Does the functionof genes change, and does the plant look different as a result?Or do the genes remain the same but carry out their task ata different time or place? Again, you can compare this to acompany. The manager stays the same but he can still arriveat a different result, for example by giving employees differenttasks or by employing new staff. By looking at how thesekinds of networks in plants are designed, and how they havechanged in different plant species, I want to find out moreabout the evolution of flowers.The networks in plants (but of course also in animals) areformed by genes and their products, proteins. Each gene is alink in the network and each protein has a specific function. Tochange the appearance of a flower, something in this networkhas to change. However, we don’t know yet what has tochange. You might only have to turn a single gene on or off tochange the network, but equally, you might have to alter theactivity of 100 genes to have a flower look different. It couldalso be that you can’t turn a gene on or off at all but that youmake a bit more or a bit less of the protein. If we understandhow the networks in flowers change, we will better understandhow other networks in organisms work.Locks and keysWe don’t know how many changes are needed in a networkto change a flower. What we do know is how the network canchange. Given a different function, a protein can bring aboutchanges in the network. Another option is that the protein isFigure 1 | The blueprint for all flowers is the same and yet the flowers all lookso different.| 21