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Is the term "cistronic", meaning an ORF on a mRNA, still commonly used in modern genetics? I´ve seen "polycistronic" being applied to prokaryotic mRNA in old textbooks, but I´ve rarely stumbled upon this in recent papers, except for research focusing on plasmid engineering.

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The thing that I think biologically interesting about this question has perhaps not been emphasized sufficiently in the answers so far which document that the term is still in use. This is why the term is still in use. As the poster states:

I’ve seen “polycistronic” being applied to prokaryotic mRNA in old textbooks, but I’ve rarely stumbled upon this in recent papers

The reason to expect that it would have fallen out of use is:

  1. The shift in research from prokaryotes to eukaryotes in the last 40 years or so
  2. The initial impression that all eukaryotic mRNAs were monocistronic.

It is the discovery of, and the interest in, exceptions* to the latter that has, in my opinion, kept the term in use. There are dicistronic and polycistronic mRNAs in eukaryotes (not just their viruses).

This is illustrated by the first two references in the answer from @theforestecologist, which refer specifically to eukaryotes in their titles.

*Footnote

The exceptions vary with species, but, to take an example that puts things into perspective, of almost 14,000 protein-coding genes in Drosophila there are only about 70 for which polycistronic mRNAs (usually dicistronic) have been established. See the p. D811 of the paper on FlyAtlas 2 and supplementary Table S6. It’s not too surprising that authors of basic text books choose to focus on generalities in an attempt to explain the main ideas in a complex subject.

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Yes, it's still used.

If you search Pubmed for "polycistronic", it offers you a chart showing the counts of the term by year (top right). Downloading the CSV and making a chart shows that it's never been a very common term, but it's still used. I suspect, but don't have time to check, that if you were to divide the use of the term by the number of published papers by year its use-per-paper would be pretty much a flat line.

Edit, re-reading the question, it may be about "cistronic" as opposed to "polycistronic". "Cistronic" is also still used, but not nearly as often as "polycistronic" -- 13 times in 2018 to "polycistronic's" 81.

enter image description here

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@iayork's answer provides a great approach to examining this question. I just want to corroborate it by using a slightly different approach.

A Google Scholar search for "polycistronic" limited to results since 2015 provides >200 hits.

Some examples include:

  • Gordon, S.P., Tseng, E., Salamov, A., Zhang, J., Meng, X., Zhao, Z., Kang, D., Underwood, J., Grigoriev, I.V., Figueroa, M. and Schilling, J.S., 2015. Widespread polycistronic transcripts in fungi revealed by single-molecule mRNA sequencing. PloS one, 10(7), p.e0132628.

  • Karginov, T.A., Pastor, D.P.H., Semler, B.L. and Gomez, C.M., 2017. Mammalian polycistronic mRNAs and disease. Trends in Genetics, 33(2), pp.129-142.

  • Liu, Z., Chen, O., Wall, J.B.J., Zheng, M., Zhou, Y., Wang, L., Vaseghi, H.R., Qian, L. and Liu, J., 2017. Systematic comparison of 2A peptides for cloning multi-genes in a polycistronic vector. Scientific reports, 7(1), p.2193.

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