Figure 3

Human RRH coding sequence and conceptual translation (peropsin) with transmembrane domains (boldface) as predicted by the rod opsin model of Palczewski et al. [48]. The six intron insertion sites in the RRH gene defined in Figure 1 are indicated by black filled circles. Equivalent intron insertion sites for the visual (rod and cone) opsins are indicated by red filled circles – intron positions 1–4 are common to all rod (RHO) and cone opsins, whilst intron 0 is only found in the LWS opsins (OPN1MW, OPN1LW) [13, 17]. The shifted second intron of the pinopsin and VA-opsin families [21, 22] are indicated as 2a and 2b respectively in red circles. Parapineal opsin [9] and encephalopsin (OPN3) [10] possess only introns 1, 3 and 4 of the rod and cone opsins. Equivalent intron insertion sites for RGR-opsin (RGR) [24] are indicated by open circles, whilst those for melanopsin (OPN4) [25] are indicated by yellow filled circles. Only intron insertion sites 1–7 for melanopsin are indicated due to the extreme length of the melanopsin C-terminus which makes positioning of introns 8 and 9 inaccurate since there is no overlap with any other opsin. Note that intron insertion sites 1 and 4 in RRH are equivalent to intron insertion sites 1 and 4 in RGR.