Expression of the gene s perm-associated antigen ( SPAG ) 5 in human adult tissues and Spag5 expression during murine development. (A) Using quantitative PCR, SPAG5 expression was detected in the human retina, brain, duodenum, kidney and testis. (B-M). RNA in situ hybridization of Spag5 mRNA in mouse embryos at embryonic day (E)12.5-E18.5 and mouse eyes at postnatal day (P)7. (B-D) Spag5 was widely expressed during murine development (E12.5 to E16.5), with the most intense signals in the following structures (numbers and arrowheads) ventricular zone of forebrain (1), midbrain (2), liver (3), lung (4), kidney (5), adrenal gland (6), thymus gland (7), submandibular salivary gland (8), limbs (9) and eye (10). (E) Expression was also seen in the cochlea, primordial vibrissal follicles, upper and lower jaw, intestine, heart, olfactory epithelium and testis (data not shown). (D) From E16.5 onwards, expression was mainly detected in the eye, brain, kidney, lung, thymus, primordial vibrissal follicles and in the liver (data not shown). (F-K) A strong signal for Spag5 was seen in the eye during embryonic development E12.5-E18.5 in the neuroblastic layer of the retina. At (I) E16.5 and (K) E18.5, Spag5 expression was present in the developing inner nuclear layer (INL; 11) and, (L-M) although much weaker, in the ganglion cell layer (GCL; 12), and this was maintained at postnatal day 7.