Growing complexity of transcription factors enabled the evolution of living beings
A research led Iñaki Ruiz Trillo, from the Department of Genetics of the UB and the Research Institute in Biodiversity (IRBio), proves that growing complexity of transcription factors play a major role in the different unicellular-to-multicellular transitions that took place in lifeʼs history. The research has been recently published in the journal Proceedings of the National Academy of Sciences (PNAS).
A research led Iñaki Ruiz Trillo, from the Department of Genetics of the UB and the Research Institute in Biodiversity (IRBio), proves that growing complexity of transcription factors play a major role in the different unicellular-to-multicellular transitions that took place in lifeʼs history. The research has been recently published in the journal Proceedings of the National Academy of Sciences (PNAS).
Transcription factors (TFs) are proteins that bind DNA and enhance or repress gene expression. Scientists analysed the repertoire and evolution of transcription factors in a wide variety of eukaryotic genomes (living beings whose cells have nucleus): plants, animals, fungi, and a wide diversity of unicellular organisms, like unicellular algae, or other types of protists like amoebas.
The research concludes that plants and animals have the most complex repertoire of transcription factors (both in the number of genes and the protein domain). Iñaki Ruiz Trillo, who is also ICREA researcher at the Institute of Evolutionary Biology (CSIC-UPF), affirms that “the great evolutionary success and the large variety of extant plant and animal forms were largely due to the acquisition of complex transcriptional regulation machinery”.
More complex transcription factors imply higher complexity in the transcriptional mechanisms and finer control of gene expression. “Animals and plants —explain scientists— have the most complex transcriptional machinery, much more than any other multicellular lineage (for instance, green and brown algae or fungi)”. Experts stress that “this can be due to the fact that both animals and plants have a complex embryonic development which requires a very strict control of gene expression and, therefore, an expanded repertoire of transcription factors”.
“This complexity did not appear suddenly but in a step-wide manner: the closest unicellular organisms to plants (that is, green algae) and animals (for instance, choanoflagellates and filastereans) have a significantly complex transcriptional regulation machinery, which was further expanded at the onset of both plants and animals lineages”, highlights Ruiz Trillo.
The study also analyses how transcription factors change throughout development. “We observed that transcription factors in animals are mainly expressed during early development”, stresses the author. “On the contrary —he adds—, transcription factors in plants remain active after early development, probably due to the formation of new structures (branches, leaves, flowers, etc.) still takes place later”.
The research is also signed by experts Àlex de Mendoza, Arnau Sebé Pedrós and Guifré Torruella, from the Department of Genetics of the UB, IRBio and the Institute of Evolutionary Biology (CSIC-UPF); Martin Sebastijan Šestak and Marija Matejčić, from Ruđer Bošković Institute (Croatia), and Tomislav Domazet Lošo, from the Catholic University of Croatia.