Jumping genes could lead to brain differences between individuals

[HuckleB]

Jumping genes in the brain

http://www.the-scientist.com/news/20050616/02

"Genetic elements that jump around the genome can influence brain circuitry, scientists report in this week's Nature. In a study of rat adult hippocampus neural stem cells, US researchers discovered an up to twofold enrichment of the transcripts of retrotransposons known as L1 elements, which can jump around the genome and comprise roughly 20% of mammalian genomes.

"We thought retrotransposition events normally only occurred in germ cells, or in very early development, the first cell stages. This is the first evidence these events might be occurring in developing neurons seen in the adult brain," Haig Kazazian at the University of Pennsylvania in Philadelphia, who did not participate in this study, told The Scientist.

To investigate how L1s might retrotranspose, the researchers used a human L1 engineered with an enhanced green fluorescent protein that activated only when the entire construct underwent retransposition. In mice bearing this construct, immunofluorescence microscopy revealed fluorescence only in germ cells and brain tissue. Moreover, fluorescence was only seen in neurons and not in astrocytes or oligodendrocytes.

"It's really surprising how selective this is for neurons," senior author Fred Gage from the Salk Institute for Biological Studies in La Jolla, Calif., told The Scientist. "We speculate that this is a mechanism for generating the diversity in the brain analogous to the immune system's ability to generate diversity in antibodies."

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JUMP!!!