purpuratus GLEAN3 gene A4 A102 A104 A108 A110 B3 B4a B6 - Bll B101 (Ap-Zic) B105 B106 B110 B114 28470: anosim-J B201 B202 + 22573: Sp-Nk7 B209 B212 B222 B227 B228 B231 B234 - B236 - 07839: SRCR
C8 + C104 C107 C111 C112 - C113 + C114 C115 C204a + C207 C210 C212 C213 C216 C219 C227 + C231 C232 D8 - D114 D127 Assigned Cross- amplified Successful (+) and unsuccessful (-) cross-amplification of each microsatellite is indicated.
There are more than a thousand SRCR
domains in the sea urchin genome, distributed in about 218 different predicted gene models, thus outnumbering those found in vertebrate genomes by a factor of 10 (Fig.
The third family of diversified sea urchin immune genes encodes an immense diversity of multidomain SRCR proteins with structural similarity to phagocytosis receptors.
It is notable that representatives of each of the sea urchin families of expanded factors (TLR, NLR, and SRCR) are part of an immune circuit in vertebrates where the DMBT1 protein, structurally very similar to the sea urchin multidomain SRCR factors, acts downstream of TLR and NLR recognition in gut immunity (Rosenstiel et al.
NLR, NACHT domain-leucine-rich-repeat protein; PAMP, pathogen-associated molecular pattern; SRCR, scavenger receptor cysteine-rich; TCR, T-cell receptor; TIR, Toll/interleukin-1 receptor domain; TLR, Toll-like receptor; VLR, variable lymphocyte receptor.