The most unlikely places

Abstract

For me humor has always been the saving grace of the human condition and I always look for humor in the most unlikely places. I will never forget telling Joan Steitz and several others at a meeting when they were planning to have an RNA Society and Journal, "How can you have a Society based on a 2 ′ hydroxyl?" Well fortunately they did not take my advice and so was born the RNA journal. Its birth throes coincided (probably intentionally) with an explosion of knowledge about RNA. (Full disclosure-this memory was sent out for historical peer review and did not fare so well, but it does lie there in the corners of my aging brain.)My first love affair however was not with RNA but with the cultured trypanosomatid flagellated parasites, Leishmania. I loved just looking at them swim around in the phase contrast microscope. And when the cells were smeared onto a slide and stained with Giemsa you could see a prominent dark blue structure at the base of the flagellum known as the kinetoplast. Maurice Steinert had shown that this was a mitochondrion that contained a large mass of DNA and, on the suggestion of William Trager, my graduate advisor, I decided to find out what it was. I thought with my usual arrogance that it would take me around two to three years and then I would look for a real thesis problem. But I arrived at UCLA in 1968 still studying the same phenomenon. Fortunately my first graduate student, Agda da Silva, took an EM lab course from Fred Eisserling and she discovered that the the kinetoplast DNA was composed of thousands of small circular DNA molecules all catenated together to form a giant DNA network. Then came the realization from the work of the Piet Borst lab that there was a second minor catenated DNA species which he called the maxicircle. We showed that the maxicircle contained mitochondrial rRNA and protein genes and the minicircles turned out to be heterogeneous in sequence and did not contain any open reading frame. This provided yet another perplexing problem which we did not solve for a few years.Well, more than 40 years later I am still studying the kinetoplast and its DNA. I did however branch out to its mitochondrial RNA, mainly because of a paper by Rob Benne with the bizzare suggestion that the mitochondrial mRNA of a related trypanosomatid differed in sequence from the DNA in having four extra uridines inserted at three sites which overcame a -1 frameshift. In those days, I didn't really believe anything until I did it myself, and when my graduate student, Janet Shaw, came into my office with a fresh autoradiograph showing that indeed kinetoplast maxicircle mRNAs in Leishmania also had extra uridines at specific sites, there were a lot more than just four nucleotides. And then another student, Nancy Sturm, came in and showed me a gel showing that there were also U deletions as well as U insertions. And then came the incredible cover of Cell from the Stuart lab that showed a pan-edited gene almost created de novo by editing. Those were heady days with this kind of mystifying data and t...