b'Genetics/Developmental BiologyDeciphering the Complexity of Cellular, Developmental, and Genetic Biology28 Surprisingly, they found that egg cells lacking FMR1 were initially normal , but with storage they lost function . . .Autism Linked to ProblemsIt was already thought that FMR1 is essential to the Creating Large Proteins last stages of the genes protein-making process. Genetic information in DNA molecules is tightly New work from Carnegies Ethan Greenblatt andbound in cell nuclei. Before the cell can read a protein Allan Spradling reveals that genetic factors underlyinginstruction, it is copied, or transcribed, by RNA, the most common cause of autism, fragile Xwhich carries code bits from the nucleus to a protein-syndrome, and potentially other related disordersmanufacturing site. The RNAs code is then translated stem from defects in the cells ability to createinto a string of amino acids.unusually large proteins.Usually these steps are rapid. However, in cells such Their work investigates the FMR1 gene. Mutationsas neurons and eggs, RNA is created and stored for of it create problems in the brain and reproductivefuture use.system, leading to fragile X syndrome and premature ovarian failure. Previous work suggested that FMR1 prevents the stored RNA molecules from overproducing new Nucleus proteins. Since many of these studies were done with DNA brain cells, Greenblatt and Spradling investigated Cytoplasm FMR1s effects on the protein-manufacturing process in the simpler fruit fly egg cell. TranscriptionSurprisingly, they found that FMR1 did not act to prevent protein overproduction, but functioned to mRNA prevent the underproduction of several hundred proteins some of which cause autism if reduced Transport to cytoplasmTranscription is the first step of turning a gene on to make a protein. It occurs in the cell nucleus (left) where a segment of DNA is copied into a complementary bit of RNA, which carries code from the nucleus to a protein-manufacturing site. The RNAs code is then translated into a protein.Image courtesy U.S. National Library of Medicine (adapted)'