Fig. 1.

Detection of adaptor protein expression. a RT-PCR was used to detect transcripts of the zebrafish nitr9, dap10, and dap12 genes in the zebrafish lymphoid and myeloid lineages. In addition to the nitr9-long (nitr9L) transcript, an alternatively spliced transcript of nitr9, nitr9-super short (nitr9SS) was detected from lymphocytes. RT-PCR of mpx provides a positive control for myeloid cells and RT-PCR of TCRα provides a positive control for lymphocytes. β-Actin is shown as a positive control for both RNA samples. A negative “no template” control was evaluated in parallel with all primer sets. b Visual representations of the three isoforms of Nitr9 are shown: The long and short isoforms were previously described (Yoder et al. 2004). Immunoglobulin (V and I) and transmembrane (TM) domains are indicated. The positive charge within the TM domain is represented by a plus sign, and a cytoplasmic tyrosine (Y) is also shown. c Sequence analyses of the nitr9SS amplicon revealed an open reading frame lacking a V domain. The predicted peptide sequence of Nitr9SS is aligned with the previously described Nitr9L and Nitr9S. Amino acid numbering of the proteins is indicated on the left. Leader sequences and transmembrane domains are boxed (note that this alignment splits the 23 residue leader sequence of NitrSS into two segments). The arginine in the transmembrane domain is indicated with white text on a black shadow. Residues which are highly conserved in immunoglobulin domains are indicated above the alignment and numbered according to the international ImMunoGeneTics (IMGT) information system (Lefranc et al. 2005). Cysteines that are conserved in NITR I domains are denoted by an asterisks above the alignment (Litman et al. 2001)