FIG. 1.
The tvbr2 allele in chicken line M contains a C125S substitution in CRD3. (A) Schematic representations of the Tvb proteins and a soluble form of Tvb fused to an mIgG are shown (not drawn to scale). The numbering of the Tvb proteins includes the signal peptide (SP) for historical reasons. MSD, membrane-spanning domain. The deduced amino acid sequences of the CRDs of the known Tvb receptors, including the turkey ortholog, TvbT, are compared, with residues different from the TvbS1 receptor indicated. The C125S substitution in TvbR2 and the C62S substitution in TvbS3 are circled. The putative disulfide bonds in the Tvb CRDs are indicated based on comparisons with the related TNFR proteins and the X-ray structure of the human DR5 TRAIL receptor protein. (B) Chromatograms of partial nucleotide and deduced amino acid sequences of CRD3s from chicken line M and outbred chicken line BL cDNAs. The G-to-C transversion is highlighted with an asterisk; the new MlyI site in line M is underlined. (C) A 1,259-bp tvb fragment was produced by reverse transcription-PCR using RNA from line BL and line M. After MlyI digestion, a 920-bp fragment was produced from the wild-type tvbs1 cDNA from line BL, while the additional MlyI site in the line M tvbr2 cDNA produced an 820-bp fragment. m, DNA marker 100-bp ladder.