The Scientist

A probe into the validity of many findings from a noted RNA researcher won't seriously set back the field, experts say—but it does cause problems, and cast doubt on at least one key advance.

Kazunari Taira, the University of Tokyo researcher, reported last year that small RNAs in mammals could silence genes via a second pathway besides a known one. That raised hopes for new therapeutic strategies against diseases including cancer.

But Taira's findings have since fallen under scrutiny, and now, "there's reason to think there isn't" this second pathway, said Bryan Cullen, professor of molecular genetics and microbiology at Duke University in Durham, NC. Taira's group has published a correction to the methods section of its Nature paper, and retracted an earlierNature paper on a different subject.

However, Cullen and other RNA-silencing specialists who have cited Taira's work told The Scientist they don't think the investigation will set back the field significantly, even if it reveals more aspects of Taira's work are invalid.

The corrected and retracted papers, along with 10 others from Taira's laboratory, fell into question last year. The RNA Society of Japan asked Taira's university to review all 12 reports after receiving complaints from several scientists who said they couldn't duplicate his findings, university officials said in a statement issued Sept. 13.

A university panel investigating the case narrowed its inquiry to four studies that would be relatively easy to investigate, according to the statement. The panel then requested the raw data for those four, the statement added. When Taira couldn't produce it, the panel asked him to repeat the experiments.

Taira told The Scientist his principal investigator failed to take notes, and instead typed data into a computer, but the machine was later discarded. He added that notes for one experiment were eventually found, so the principal investigator will repeat three experiments. Taira also said he plans to check researchers' notes at all future laboratory meetings.

"I feel very sorry for other young scientists in my group" who are unfairly tainted, said Taira, a professor of chemistry and biotechnology, noting that some have been asked to cancel symposium appearances.

Taira's Nature paper on the second gene-silencing pathway was just one of two, published almost simultaneously, reporting its existence. But this still doesn't confirm it, Cullen said: many labs have been looking for this pathway, which does exist in plants, and involves transcriptional-level, as opposed to post-transcriptional, silencing. "Everybody and their dog did the experiment," he said. "The ones who got the results are the ones who got published. And there hasn't been any followup." Thus the finding remains unconfirmed, he says. Authors of the other paper reporting the second pathway couldn't be reached for comment.

Overall, Taira's case won't set back the RNA field, V. Narry Kim, professor of molecular biology at Seoul National University in Korea, told The Scientist, because "investigation in just one lab doesn't really affect the general trend" of research. Cullen agreed, saying Taira hasn't made big enough breakthroughs to change the field.

"I think basically Dr. Taira is a respectable person," Kim added. "I met him and did some research with him last year and this year," and found him to be a careful researcher. "I don't believe he actually made up" results, though someone in his lab may have discarded inconvenient data, she added.

James Carrington, director of the center for genome research and biocomputing at Oregon State University in Corvallis, who has cited Taira's work, painted a less generous picture of Taira, saying his retracted paper contained "incredibly sloppy" work. It purported to analyze one gene, yet presented sequences for a different gene, he told The Scientist. "Was it fraud? Was it an honest mistake? One cannot tell for now," he said. However, Carrington noted he did not believe his own results would be affected by the retracted paper.

But cases of this type can causes ripples, Carrington added: science gets a poor image, bad references can litter the literature, and scientists waste time trying to replicate possibly unreproduceable work. "We just don't have the person-power and the time to be repeating all work, unless we're in the process of extending it," he said.