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Chinese scientists row over long-sought protein that senses magnetism
Two universities ask journal to retract paper that allegedly violated a
collaboration agreement.
David Cyranoski
21 September 2015
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Neuroscientists in China say they have used magnetic fields to control
neurons and muscle cells in nematode worms (pictured), after identifying a
protein that senses magnetism.
A dispute has broken out at two of China’s most prestigious universities
over a potentially groundbreaking discovery: the identification of a protein
that may allow organisms to sense magnetic fields.
On 14 September, Zhang Sheng-jia, a neuroscientist at Tsinghua University in
Beijing, and his colleagues published a paper1 in Science Bulletin claiming
to use magnetic fields to remotely control neurons and muscle cells in
worms, by employing a particular magnetism-sensing protein.
But Xie Can, a biophysicist at neighbouring Peking University, says that
Zhang’s publication draws on a discovery made in his laboratory, currently
under review for publication, and violates a collaboration agreement the two
had reached. Administrators at Tsinghua and Peking universities, siding
with Xie, have jointly requested that the journal retract Zhang’s paper,
and Tsinghua has launched an investigation into Zhang’s actions.
The dispute revolves around an answer to the mystery of how organisms as
diverse as worms, butterflies, sea turtles and wolves are capable of sensing
Earth’s magnetic field to help them navigate. Researchers have postulated
that structures in biological cells must be responsible, and dubbed these
structures magnetoreceptors. But they have never been found.
Disputed agreement
In research starting in 2009, Xie says that he used a painstaking whole-
genome screen to identify a protein containing iron and sulfur that seems,
according to his experiments, to have the properties of a magnetoreceptor.
He called it MagR, to note its purported properties, and has since been
examining its function and structure to determine how it senses magnetic
fields.
While Xie waited for his paper to make it through peer review — a process
that started in December 2014 — a handful of groups initiated
collaborations with him in hopes of using MagR as a research tool. He shared
the protein, related biological materials and data, on the condition that
other groups would let him publish his discovery first and include him as a
co-author in their papers. “I never really worried about it because we all
agreed that the paper determining the protein should be first,” says Xie.
Xie shared information and biological materials with Zhang, but the two
contest the details of their agreement. Zhang says that he agreed to Xie’s
conditions, but that Xie also promised not to share the data with anyone
else. And Zhang says that after he heard that Xie had “leaked” his data,
he felt that he no longer needed to honour the agreement.
But Xie says that he made no such promise to Zhang. “Why would I?” he says
. Xie says that he was collaborating with another Tsinghua University
neuroscientist, Lu Bai, and shared information with Zhang because he
mistakenly believed that Zhang was part of Lu’s research team. He said that
he gained that impression after Zhang accompanied Lu’s student on a visit
to Xie’s lab in April. Zhang, meanwhile, says that he and Xie had forged an
agreement independent of Lu, something Xie denies.
Approached for comment, Lu says that Tsinghua has asked him not to discuss
the matter — but documents seen by Nature show that the university has
launched an investigation into Zhang’s actions after Lu complained that
Zhang stole his research materials and ideas.
Magnetic 'magic'
The contents of Zhang's paper have sparked debate and some doubt. In the
work — which was submitted on 9 September, accepted on 11 September and
published three days later — Zhang uses the same protein that Xie had
identified, but calls it MAR, not MagR. He reports experiments using
magnetic fields to manipulate cells engineered to express the protein. For
example, by engineering worms to have MAR active only in muscles, he uses
magnetism to make their muscles contract. And by engineering them to have
MAR only in certain neurons related to sensitivity to touch, he reports that
magnetic fields made the worms withdraw, as if reacting to physical touch.
The report is preliminary, but shows the potential of using the protein and
magnetic fields to stimulate neurons, says Mu-ming Poo, director of the
Institute of Neuroscience at the Chinese Academy of Sciences in Shanghai.
But he and other researchers are critical that the paper does not discuss
how the protein can sense magnetic fields. James Chou, a biological chemist
at Harvard Medical School in Boston, Massachusetts, says that the work
offers no reasonable explanation — or even speculation.
“They don't really seem to understand why this protein appears to be
magnetic,” says Peter Hore, a biochemist at the University of Oxford, UK.
He says that the description of the protein central to the experiment is
inaccurate. The paper speculates that the proteins form as “magnetosomes”.
But Hore points out that this is a term generally used for structures
composed of magnetic minerals, rather than proteins. “They’ve confused a
cluster of iron and sulfur atoms in a protein with a mineral that contains
no protein at all,” he says.
Zhang concedes that he is unclear on how the protein might work. But he says
that the important thing is that “we know how to trigger robust activity
with this magical molecule”. The paper has three other co-authors, whom
Zhang says are all his graduate students. Nature has not been able to
contact them, and Zhang has refused to provide their e-mail addresses,
saying that he had to check with the university whether it was OK to do so.
Academic ethics
In an e-mail seen by Nature, administrators from Tsinghua and Peking
universities say they have asked the journal to retract Zhang's publication.
They say that by proceeding without Xie's permission, Zhang's paper "
violated academic norms". Asked for comment, editors at Science Bulletin
acknowledged receiving the message, but said that their actions “will
depend on the results of the investigation provided by the institutions.”
The journal is co-published by Science China Press and Springer; a
spokesperson for Springer said the publisher was currently looking into the
matter and had no further comment to make at this time.
Zhang told Nature that he thinks his research will win a Nobel prize. He
says that he was justified in publishing the results because Xie’s work was
merely biochemical identification, whereas he had the idea of using
magnetic fields and the protein to control cells. Xie says that this idea is
obvious, and that he included it in a patent he applied for last year.
Whatever the result of the dispute, scientists whom Nature has spoken to are
excited by the prospects of finally identifying a magnetoreceptor in cells
— whoever turns out to have done it. “To know the molecular basis of using
proteins to sense magnetic fields would be incredible!” says Chou.
Nature doi:10.1038/nature.2015.18397
