NEW FUNCTION FOR tRNA - C&EN Global Enterprise (ACS

Mar 22, 2010 - ... led by University of Pennsylvania cancer biologist Xiaolu Yang ( Mol. .... (ACS) named Professor Thomas Holme of Iowa State Univers...
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NEWS OF THE WEEK

INDIAN FIRMS EXPAND ABROAD SPECIALTIES: India’s chemical makers snap up Western assets

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NDIA’S KIRI DYES & CHEMICALS has acquired Dy-

DYSTAR

DyStar’s plant in Brunsbüttel, Germany, will likely close.

Star, one of the world’s largest producers of dyes. The move underlines an increasing appetite for foreign assets by India’s specialty chemical producers, which until recently were mostly focused on their home market. Kiri, which has its headquarters in Ahmedabad in the northwest state of Gujarat, paid less than $70 million for DyStar, a German firm that employs 3,500 and has manufacturing facilities around the globe. Kiri will not assume financial responsibility for DyStar’s German employees or bank debts in Germany, a point that Kiri says was a crucial part of the negotiations. DyStar filed for bankruptcy in Germany last fall (C&EN, Oct. 26, 2009, page 16). Kiri says it plans to make the firm profitable again by “replacing highcost German manufacturing base with low-cost manufacturing in India and China.” The German firm was formed in 1995 through a merger of the dyes busi-

NEW FUNCTION FOR tRNA

LILY GUO/U OF PENNSYLVANI A

Binding of tRNA (middle, green and yellow) to cytochrome c (red) released by a mitochondrion (left) limits formation of a complex that promotes apoptosis (top right).

CELL BIOLOGY: Transfer RNA

keeps apoptosis in check

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EW FINDINGS indicate that transfer RNA

(tRNA) has another function in addition to its long-established role in gene expression. tRNA also helps control apoptosis, or programmed cell death, according to a team of researchers led by University of Pennsylvania cancer biologist Xiaolu Yang (Mol. Cell 2010, 37, 668). During gene expression, DNA is first transcribed into messenger RNA. Next, tRNA molecules—each carrying an amino acid as cargo— bind to successive nucleotides in the messenger RNA. A ribosome links these amino acids together to form a protein, WWW.CEN-ONLINE.ORG

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nesses of Bayer and the now-defunct Hoechst. In 2000, BASF transferred its dyes business to DyStar. The purchase underscores an ongoing global expansion by India’s specialty chemical producers. “For some time now, the capital markets in India have been robust, and companies here command a good valuation, giving them the ability to raise capital cheaply,” explains Pramod Menon, head of marketing at Dorf Ketal Chemicals, an Indian producer of catalysts and refinery chemicals. At the same time, Indian specialty chemical makers have “an appetite for global expansion and access to foreign markets,” Menon says. Dorf Ketal itself has made a series of acquisitions in recent years, including that of a DuPont catalyst business (C&EN, Feb. 15, page 36). Similarly, late last month, India’s Artek Surfin Chemicals bought Chemtura’s polyvinyl chloride additives business for $48 million. With 250 employees and plants in Germany and Louisiana, the business generated sales of $236 million in 2009. Artek says it will widen its acquisition’s product range and expand sales of vinyl additives in Asia. It will also make use of the unit’s sales force to boost sales of Artek’s existing product line in Europe and North America. Until now, Artek has mostly been a producer of chemicals used in metal finishing, electroplating, and printed circuit board production.—JEAN-FRANÇOIS TREMBLAY

and the unloaded tRNAs are subsequently released. Now, “for the first time, we show that tRNA has a clear role beyond the transmission of genetic information,” Yang says. “It actually blocks apoptosis.” Apoptosis eliminates unwanted, damaged, or harmful cells. It can be triggered by signals from either inside or outside a cell. Internal signals, such as DNA damage, prompt the cell’s power generators, or mitochondria, to release cytochrome c into the intracellular fluid, known as the cytosol. Mitochondria normally use cytochrome c to produce adenosine triphosphate, which powers metabolism. But when it’s released into the cytosol, cytochrome c instead binds to the protein Apaf-1, which activates caspases that cleave various cellular proteins, ultimately killing the cell. Yang, along with Yide Mei, Jeongsik Yong, and other colleagues, have discovered that tRNA also binds to cytochrome c, stopping it from binding to Apaf-1 and thereby preventing apoptosis. The researchers have “unveiled a completely unexpected level of control in the apoptotic process,” comment Bram J. van Raam and Guy S. Salvesen, who study apoptosis and cell death at Sanford-Burnham Medical Research Institute, in La Jolla, Calif. (Mol. Cell 2010, 37, 591). Raam and Salvesen suggest the findings also “might indicate a new and important level of nuclear control over mitochondrial metabolism.” tRNA is highly expressed in tumor cells. It inhibits apoptosis in these cells, Yang believes, and could thus be targeted for tumor therapy.—SOPHIE ROVNER

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