RNAi and telomere length

A team of Russian scientists, led by Dr. Vladimir Gvozdev (Russian Academy of Sciences) reports on a novel link between RNAi and telomere maintenance in the Drosophila germline. Unlike most eukaryotes, which use the enzyme telomerase to lengthen their chromosome ends, Drosophila telomeres are maintained by specialized telomeric retrotransposons (Het-A, TART and TAHRE) that are attached, or transposed, onto chromosome ends.

Dr. Gvozdev and colleagues have discovered that two known components of the Drosophila RNAi machinery regulate the transposition of these telomeric retrotransposons. The researchers show that mutations in either spindle-E (an RNA helicase) or aubergine (an Argonaute family member) cause an increased frequency of telomere element transposition onto broken chromosome ends in ovary cells.

"Our data highlight the regulatory role of an RNAi-based mechanism, earlier considered as a defense system against retrotransposon and virus expansion, in telomere maintenance," explains Prof. V. Gvozdev. Dr. Kalmykova, first author on the paper, also points out that "We suggest that RNAi-mediated regulation of telomere dynamics in the germline may be a general phenomenon in distinct organisms, because all known telomeres include repetitive elements, a potential target of RNAi."

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