U. researchers find gene splicing in the absence of nucleus

Utah researchers have shown that a key process in gene regulation can occur in blood platelets despite the lack of a nucleus.

Scientists have thought that splicing, a process where pre-messenger RNA transforms into mature messenger RNA, only happens in a cell's nucleus. But researchers at the University of Utah School of Medicine reported in the Aug. 12 edition of Cell that they found that splicing also took place in blood platelets.

"Many people would never have thought that the platelets could do this because it just didn't have the key command and control center, the nucleus," said Dr. Guy A. Zimmerman, professor of internal medicine and one of the study's co-authors. "In every example and study up to this point it has all been done in the nucleus."

The U. researchers were studying how platelets communicate with certain white blood cells when they discovered that platelets were making new proteins.

"The idea that blood platelets could make proteins without having a nucleus had been thought heretical," Zimmerman said. "To find that splicing takes place outside the nucleus has potential implications beyond the platelet."

Zimmerman said that the research raises the possibility that splicing could occur in other specialized cells a long way from the nucleus.

"It could be that splicing could go on at these far distant places if it could occur in platelets that don't have a nucleus at all," Zimmerman said.

The researchers used stem cells from human umbilical cord blood to create the precursor cell that forms platelets, as well as platelets isolated from the blood of study subjects, and found that splicing takes place in the platelets.

The researchers found one protein, Interleukin 1, that is made through the splicing process in platelets.

Zimmerman said Interleukin 1 is important in blood clotting and in inflammation.

"It's the kind of molecule that gets turned on at the wrong place or the wrong time in a variety of inflammatory diseases," Zimmerman said.

Interleukin 1 can contribute to diseases like atherosclerosis, the hardening of the arteries, and rheumatoid arthritis if it is formed in the wrong place and the wrong time, Zimmerman said.