IDENTIFICATION OF NOVEL IMMUNE MEDIATORS IN THE TRANSCRIPTOME OF STRONGYLOCENTROTUS PURPURATUS COELOMOCYTES

13 Jun 2017
14:30 - 14:45

IDENTIFICATION OF NOVEL IMMUNE MEDIATORS IN THE TRANSCRIPTOME OF STRONGYLOCENTROTUS PURPURATUS COELOMOCYTES

Sebastian Fugmann, Chang Gung University

Mei-Chen Liu1, Wen-Yun Liao1, Katherine M Buckley4,5,6, Shu Yuan Yang1,2,7, Jonathan P. Rast4,5,6, Sebastian D. Fugmann3,8,9

1. Department of Biomedical Sciences, 2. Division of Biochemistry, Molecular and Cellular Biology,
Graduate Institute of Biomedical Sciences, 3. Division of Microbiology, Graduate Institute of
Biomedical Sciences, Chang Gung University, Tao-Yuan, Taiwan
4. Biological Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
5. Department of Medical Biophysics, 6. Department of Immunology, University of Toronto, Toronto, Ontario, Canada
7. Department Of Pathology, 8. Department of General Surgery, Chang Gung Memorial Hospital, Tao-Yuan, Taiwan
9. Chang Gung Immunology Consortium, Chang Gung Memorial Hospital and Chang Gung University, Kwei-Shan District, Tao-Yuan, Taiwan

The genome of the purple sea urchin (Strongylocentrotus purpuratus) contains a number of genes whose products have previously been implicated as important mediators of adaptive immunity. This includes the S. purpuratus homologs of the recombination activating genes 1 and 2 (SpRag1L and SpRag2L) whose vertebrate cousins are critical for the assembly of the antigen receptors genes that are a hallmark of adaptive immunity. These findings suggest that echinoderms are placed at an important transition point between innate and adaptive immunity. To gain insight into the function of sea urchin immune cells we initiated a RNAseq-based analyses of the transcriptomes of the four most abundant coelomocyte types. We discovered a large number of genes expressed specifically in distinct coelomocyte types, but we also identified numerous novel transcripts for which the corresponding genes have not been annotated yet. This includes a novel family of AID/APOBEC-like cytidine deaminases. Interestingly, the AID/APOBEC deaminases were previously thought to be exclusive to vertebrates, but our extended database searches now reveal the presence of numerous genes encoding such enzymes throughout the invertebrate world. Taken together, the findings from our coelomocyte transcriptome dataset are in line with the emerging concept that the adaptive immune system including factors that are now fount to be central to vertebrate adaptive immunity, appeared much more gradually than previously anticipated.

This work was supported by Chang Gung Memorial Hospital grants (CMRPD1C0242,
CMRPD1F0421, CORPD1F0051) and a Ministry of Science and Technology grant (102-2320-
B-182 -001 -MY3) to SDF.