In a discovery that blurs the boundaries between human genetics and virology, scientists have identified a human gene embedded in a poxvirus, and it\u2019s no ordinary gene. The gene, called BC200, is both essential for brain function and a \u201cjumping gene\u201d that can move and insert itself into genomes.<\/p>\n
Published in Science on Sept. 24, the study reveals a genetic oddity with implications for evolution, disease, and even viral biology.<\/p>\n
BC200 is mostly expressed in neurons, where it likely helps regulate how messenger RNAs are translated into proteins. It originated millions of years ago from a transposon, a mobile genetic element often dismissed as \u201cjunk DNA<\/a>.\u201d<\/p>\n Transposons can disrupt genes when they insert themselves, but over evolutionary time they have also been repurposed into useful functions.<\/p>\n Jumping DNA plays a significant role in regulating human neurons<\/a><\/p>\n What makes BC200 unique is that it has retained its mobility while also serving a vital cellular role.<\/p>\n \u201cGenes that come from transposable elements and that are repurposed for cellular functions are typically no longer transposable,\u201d said Cedric Feschotte, the study\u2019s senior author. \u201cBC200 was itself created from a mobile element but has retained its mobility, and yet it is also clearly serving a cellular function. Somehow evolution hasn\u2019t been able to untangle these two things.\u201d<\/p>\n The story began in 2010, when researchers found BC200 insertions in molluscum contagiosum virus (MCV), a human poxvirus that causes benign skin warts. The gene appears to have jumped into MCV twice in human history, roughly 100,000 years ago. This is one of the rare documented cases of a vertebrate transposable element escaping into a virus in the wild.<\/p>\n Such events raise intriguing possibilities: if viruses can carry transposons across species boundaries, they may act as vehicles for spreading genetic elements between organisms.<\/p>\n BC200\u2019s progenitor was co-opted in primates about 40 million years ago. Today, it is found only in humans and related primates. Its presence in neurons suggests a role in brain function, but it is also expressed in germ cells, meaning it could generate inheritable insertions.<\/p>\n The gene\u2019s mobility may not always be benign. BC200 is abnormally expressed in certain tumors and overexpressed in the brains of Alzheimer\u2019s patients<\/a>, hinting that its jumping ability could contribute to disease.<\/p>\n