Fig. 1. Positions of the amino acid substitutions in the gea1-4, gea1-6 and gea1-19 alleles. Sequence alignments (with three other ARF GEFs) of the regions of Gea1p in which these changes occur are indicated. GenBank accession numbers for the sequences shown are: Gea1p (Z49531); Gnom/Emb30 (U36433); C. elegans ARF GEF (Z81475); and GBF1 (AF068755). The Sec7 domain of Gea1p is indicated by a striped box. gea1-4 has additional substitutions in the C-terminal portion of the protein downstream of the Sec7 domain, but these are in poorly conserved regions of the protein. gea1-6 has only the two substitutions shown. gea1-19 has two additional substitutions, but only those in regions of clearly defined homology among the four ARF GEFs shown are indicated. Note that gea1-6 and gea1-19 both have one substitution, L862S and M859K, respectively, in the same well-conserved region. Identities in the sequence alignment are boxed, and similarities are shaded.