- Email: [email protected]
Protein discovery could lead to ‘genomic debuggers’
Lange R, Gerlach T, Beninde J, Werminghausen J, Reichel V, et al
IN BRIEF Cool clue to body clock’s workings
Hermaphrodite sea slugs benefit from rough sex THERE’S an upside to being repeatedly stabbed – at least if you’re a hermaphroditic sea slug. Siphopteron quadrispinosum is a simultaneous hermaphrodite: each animal has male and female sexual organs, and it can use both at once. An animal acting as a male uses a syringe-like organ to stab its partner and inject prostate fluid into its body. The “male” then inserts its penis into the partner’s genital opening; the penis has spines that anchor it in place. Because mating is so traumatic for the “female”, the slugs prefer to act male. Curiously, though, Rolanda
Lange of the University of Tübingen in Germany, and colleagues, found that captive sea slugs produced the same proportion of fertilised eggs no matter how many times they mated as a female. This suggests that many of the slugs were taking on a “female” mating role more often than necessary for reproductive success, perhaps because the traumatic mating has some benefit that offsets the bodily harm (PLoS ONE, doi.org/h7c). We don’t know what that advantage might be, says Mike Siva-Jothy of the University of Sheffield, UK. But the injections of prostate fluid might include nutrients that benefit the stabbed slug. Male insects often proffer food as a bribe to persuade females to mate. “Male” sea slugs might be doing the same thing. “Males are giving with one hand and taking with the other,” Siva-Jothy says.
Code for RNA repair is cracked THE trick could have come from a thrifty plumber: why replace a leaky pipe if you can simply patch it up? A single fault in DNA can travel a long way. It may be copied into RNA, which then produces the faulty proteins that underlie some genetic disorders. Now biologists have laid the groundwork for creating tools designed to bind to faulty RNA 14 | NewScientist | 1 September 2012
and fix protein production. The tools are themselves proteins. Ian Small at the University of Western Australia, Crawley, and his colleagues identified a special class of RNA-binding proteins 12 years ago. “One vision of their activity is as genomic debuggers – they correct mutations at the RNA level,” he says. Small’s team has now worked
out how their RNA-binding proteins, called PPR, latch on to RNA. PPR proteins carry a pattern of amino acids that binds to the bases on RNA. The team realised that just two amino acids in each pattern determine exactly which part of an RNA molecule the PPR protein binds to (PLoS Genetics, doi.org/h7b). The finding paves the way for building “designer PPR proteins” that target and fix specific genes, Small says.
A PROTEIN that becomes more abundant when temperatures fall could be the key to how our cells keep time. The brain imposes small daily swings in body temperature to help ensure that the body follows its 24-hour clock. But the details of how cells fall into step are unclear. Jörg Morf at the University of Geneva, Switzerland, and his colleagues exposed mouse cells to cycling temperatures. They found that levels of a protein called CIRP, which is known to be activated when temperatures fall, cycled too. Then they found that CIRP binds to RNA regions associated with the production of certain proteins that help regulate the cell’s internal clock. Levels of these proteins also vary with body temperature. Blocking CIRP production reduced the variation in these proteins, suggesting it is essential to our body clock (Science, DOI: 10.1126/science.1217726).
Giant and dwarf spawn a supernova ONCE upon a time, a red giant star blew so much material onto a nearby white dwarf star that the dwarf exploded, creating what is called a type Ia supernova. This tale is the best explanation for supernova PTF 11kx, says a team led by Ben Dilday at the University of California, Santa Barbara (Science, doi.org/h7h). The work suggests that not all type Ia supernovae have the same trigger, because other such stellar explosions seem to start when two white dwarfs merge. Type Ia supernovae are all of roughly the same brightness and so are used as “standard candles” for measuring cosmological distances. Knowing what causes variations in brightness could improve measurement accuracy.
IN BRIEF Cool clue to body clock’s workings
Hermaphrodite sea slugs benefit from rough sex THERE’S an upside to being repeatedly stabbed – at least if you’re a hermaphroditic sea slug. Siphopteron quadrispinosum is a simultaneous hermaphrodite: each animal has male and female sexual organs, and it can use both at once. An animal acting as a male uses a syringe-like organ to stab its partner and inject prostate fluid into its body. The “male” then inserts its penis into the partner’s genital opening; the penis has spines that anchor it in place. Because mating is so traumatic for the “female”, the slugs prefer to act male. Curiously, though, Rolanda
Lange of the University of Tübingen in Germany, and colleagues, found that captive sea slugs produced the same proportion of fertilised eggs no matter how many times they mated as a female. This suggests that many of the slugs were taking on a “female” mating role more often than necessary for reproductive success, perhaps because the traumatic mating has some benefit that offsets the bodily harm (PLoS ONE, doi.org/h7c). We don’t know what that advantage might be, says Mike Siva-Jothy of the University of Sheffield, UK. But the injections of prostate fluid might include nutrients that benefit the stabbed slug. Male insects often proffer food as a bribe to persuade females to mate. “Male” sea slugs might be doing the same thing. “Males are giving with one hand and taking with the other,” Siva-Jothy says.
Code for RNA repair is cracked THE trick could have come from a thrifty plumber: why replace a leaky pipe if you can simply patch it up? A single fault in DNA can travel a long way. It may be copied into RNA, which then produces the faulty proteins that underlie some genetic disorders. Now biologists have laid the groundwork for creating tools designed to bind to faulty RNA 14 | NewScientist | 1 September 2012
and fix protein production. The tools are themselves proteins. Ian Small at the University of Western Australia, Crawley, and his colleagues identified a special class of RNA-binding proteins 12 years ago. “One vision of their activity is as genomic debuggers – they correct mutations at the RNA level,” he says. Small’s team has now worked
out how their RNA-binding proteins, called PPR, latch on to RNA. PPR proteins carry a pattern of amino acids that binds to the bases on RNA. The team realised that just two amino acids in each pattern determine exactly which part of an RNA molecule the PPR protein binds to (PLoS Genetics, doi.org/h7b). The finding paves the way for building “designer PPR proteins” that target and fix specific genes, Small says.
A PROTEIN that becomes more abundant when temperatures fall could be the key to how our cells keep time. The brain imposes small daily swings in body temperature to help ensure that the body follows its 24-hour clock. But the details of how cells fall into step are unclear. Jörg Morf at the University of Geneva, Switzerland, and his colleagues exposed mouse cells to cycling temperatures. They found that levels of a protein called CIRP, which is known to be activated when temperatures fall, cycled too. Then they found that CIRP binds to RNA regions associated with the production of certain proteins that help regulate the cell’s internal clock. Levels of these proteins also vary with body temperature. Blocking CIRP production reduced the variation in these proteins, suggesting it is essential to our body clock (Science, DOI: 10.1126/science.1217726).
Giant and dwarf spawn a supernova ONCE upon a time, a red giant star blew so much material onto a nearby white dwarf star that the dwarf exploded, creating what is called a type Ia supernova. This tale is the best explanation for supernova PTF 11kx, says a team led by Ben Dilday at the University of California, Santa Barbara (Science, doi.org/h7h). The work suggests that not all type Ia supernovae have the same trigger, because other such stellar explosions seem to start when two white dwarfs merge. Type Ia supernovae are all of roughly the same brightness and so are used as “standard candles” for measuring cosmological distances. Knowing what causes variations in brightness could improve measurement accuracy.