Gene Length Matters
Research reveals a surprising fact about human genes when a protein-coding gene is too short it becomes inactive!
The findings from Aarhus University also explain how some short genes have adapted to circumvent this handicap.
Human genomes harbour thousands of genes, each of which gives rise to proteins when it is active. But which inherent features of a gene determine its activity?
Researchers have now found that the distance
between the gene start, termed the ‘promoter,’
and the gene end, the ‘terminator,’
is crucial for the activity of a protein-coding gene.
If the distance is too short,
the gene is transcriptionally repressed
and that gene's output severely decreased.
This finding outlines a completely new
functional interplay between gene ends.
The research team includes Postdoctoral Scholar, Pia Kjølhede Andersen, and Senior Researcher, Søren Lykke-Andersen from the Danish National Research Foundation’s Centre for mRNP Biogenesis and Metabolism. Their work was published in Genes & Development
Small genes utilise specialised terminators
Fortunately, most human protein-coding genes are long and are therefore not repressed by this mechanism. However, some genes, e.g. ‘replication-dependent histone genes’, are very short. How do such genes express their information at all? Interestingly, many of these differ from the longer protein-coding genes by containing specialised terminators. And in fact, if such a specialised terminator replaces a normal terminator in a short gene context, the short gene is no longer transcriptionally repressed.
It appears that naturally occurring short genes
have evolved ‘their own’ terminators
to achieve high expression levels.
The new findings add to a complex molecular network of intragenic communication and help us to understand the basic function of genes.
The researchers behind the results that have just been published in the international journal Genes & Development are affiliated with the Danish National Research Foundation’s Centre for mRNP Biogenesis and Metabolism at the Department of Molecular Biology and Genetics, Aarhus University.
Link to the article in Genes & Development:
Promoter-proximal polyadenylation sites reduce transcription activity
Pia K. Andersen, Soren Lykke-Andersen, and Torben Heick Jensen
Department of Molecular Biology and Genetics, Centre for mRNP Biogenesis and Metabolism, C.F. Møllers Allé, Building 1130, Aarhus University, 8000 Aarhus C, Denmark
Original article: http://mbg.au.dk/en/news-and-events/news-item/artikel/length-matters-in-gene-expression/