Fig. 4. Molecular characterization of td1. (A) CLUSTALW alignment of TD1 (from B73 inbred line; top line) and CLV1 (below, GenBank Accession No.: 15222877). Identical residues are outlined in black, similar in gray; dashes represent gaps introduced to optimize the alignment. The black arrow indicates the position of the single intron. Predictions of transmembrane and signal sequences are by SMART (http://smart.embl-heidelberg.de/) for TD1 and from Clark et al. (Clark et al., 1997) for CLV1. Domains are labeled below the respective sequences; yellow, signal peptide; gray, extracellular LRR domain, numbering of single LRR motifs; blue, transmembrane domain; red, kinase domain (the 12 subdomains are labeled SDI-SDXII). Cysteine pairs are marked by asterisks above the respective sequences. The defect in the polypeptide encoded by td1-Ref is shown above TD1. (B) Schematic representation of the Mu element insertion sites within the different td1 alleles.