Figure 1

Sequence information on Ubx, Antp and Ubx/Antp. (A) Conserved N-terminal region of UBX and hexapeptide sequence of UBX and ANTP in arthropods. Dashes indicate conserved positions, dots represent gaps, question marks stand for unknown sequence. Amino acids contributing to the homeodomain are underlined. (B) Overview of bicistronic transcripts of Ubx/Antp and their splice variants in arthropods. Ubx sequence is in light grey; Antp sequence is in dark grey; positions of primers for the detection of Ubx/Antp are indicated by arrows. In splice variant I, Antp is almost exactly abutting the open reading frame of Ubx with only few base pairs of Ubx 3' UTR in between. In splice variant II, all sequence of Antp 5' to the homeodomain (HD) is missing. (B) Sequences of the Ubx/Antp splice variant II from Glomeris, Euperipatoides and Artemia. The homeodomain is underlined, primers are shaded, and the 3' UTR of Ubx is in bold. (C) Extension of isolated Ubx mRNA and inferred extension of the aUbx transcript. Probes (P1 to P5) detecting Ubx and aUbx are indicated (not to scale). Whether 5'- and 3' UTR transcripts extend beyond the detected area is unclear (question marks). Positions of start codon (ATG), hexapeptide (hex), homeodomain (HD), stop codon (TAA) and poly-A tail (dot__AAAAAA) are indicated. (D) Twelve conserved 21bp-repeats situated in the 3' UTR of Glomeris Ubx. The sequences are abutting each other without bases in between. Consensus sequence is on top. Differences from the consensus are marked by shaded bases, changed amino acids are in bold.