Phylogenetic conservation of miR-183 family members and expression in vertebrate sensory organs. (A) Representative bilaterian organisms that contain miR-183 family members include vertebrates (black) among invertebrate deuterostomes (blue) and protostomes (red). Asterisks indicate species for which certain miR-183 family members are supported by genomic sequence data (see Materials and Methods). The question mark indicates that no miR-183 family members have been identified among diploblasts (green). (B) Sequence alignment of conserved vertebrate miR-183 family members (black) with those identified among other deuterostomes (blue) and protostomes (red). Nucleotide substitutions or deletions (−) are colored orange. (C) ISH detecting miR-183 demonstrates expression in vertebrate hair cells (hc). Depicted are salamander skin neuromasts (n) and ampillary (electroreceptive) organs (a) in whole-mount and cross-section superimposed upon false-colored DAPI-labeled nuclei (red). Hair cell staining in whole-mount ampillary organ (dashed box) is shown in a different focal plane in the inset (solid box). Whole-mount lamprey and hagfish ears show hair cell staining in the common macula (mc), anterior crista (ac), posterior crista (pc), and dorsal crista (dc; lamprey only). Scale bars indicate 100 μm for salamander skin and 1 mm for lamprey and hagfish ears.

miR-183 family member expression in sea urchin tube feet. (A) ISH detecting moderate expression of spu-miR-183-like in the sucker cup rim of green sea urchin tube feet compared to negative control lacking probe. (B) Tubulin ICC demonstrates innervation of spu-miR-183-like positive regions containing cilia (arrowheads). Scale bars indicate 100 μm. (C) spu-miR-183-like-primary transcript expression is specific to tube feet. Depicted is primary transcript detection relative to U6 snRNA by RT-PCR of total RNA isolated from sea urchin digestive gland (D), gonad (G), and tube feet (T) in reactions prepared with (+) or without (−) reverse transcriptase (RT) along side 100 bp ladder (L).

miR-183 family member expression in acorn worm is associated with putative sensory regions. (A) ISH detecting miR-183 expression in epithelial cells of the acorn worm proboscis (P), second collar region (C2), and dorsolateral regions posterior to the gill slits and ciliated band. (B) Association of miR-183 expression with putative sensory regions of acorn worm proboscis and collar. Clockwise from upper left: tubulin ICC demonstrates specific innervation of C2, BDNF ICC shows neurotrophin expression in C2, and Prox1 and MyoVIIa ICC respectively demonstrate strongest expression in C2 and proboscis. Scale bars indicate 50 μm.

miRNA-183 family member expression in sensory organs of protostomes. (A) ISH detecting miR-263b expression in fruit fly mechanosensory and chemosensory antennal segments 2 and 3, respectively (A2 and A3; top left), and haltere (bottom left). Cross-sectional views of the Johnston’s organ (A2; top right) and haltere (bottom right) indicate miR-263b expression in scolopidia and campaniform sensilla, respectively, superimposed upon false-colored DAPI-labeled nuclei (red). (B) miR-228 expression in C. elegans indicated by miR-228p::GFP transgene expression. miR-228 expression is indicated in cells provisionally identified as sheath and/or socket cells of phasmid (PH), posterior deirid (PD), and anterior sensilla (AS) including inner/outer labial (I/OL), cephalic (CEP), and amphid (AM). Phase contrast (top) and fluorescence (center) images are superimposed (bottom) for each lateral view of the anterior (left), middle (center), and posterior (right) region of the worm. Seam cell (SC) expression is also indicated. Scale bars indicate 50μm.