(A) An unrooted
phylogenetic tree of ADF-H domains. This tree was produced by
subjecting the alignment depicted in Figure 2 to analysis by the
Clustal-W software package (Thompson et al., 1994). An
allowance was made for multiple substitutions (Kimura, 1983).
Information from intervals in the alignment for which gaps are found in
some sequences was included. (Note: the tree architecture is almost
identical if gaps are omitted.) The tree was tested (1000 trials) for
branching order confidence by bootstrapping (Felsenstein, 1985). Filled
circles indicate branch points supported beyond a confidence level of
85%. Empty circles indicate branch points supported beyond the 50%
but below the 85% confidence level. Dashed lines indicate the three
classes described in this essay. A bar showing 5% divergence is
included. Further information on this procedure (as applied to myosin
motor domains) can be found on the Worldwide Web at
http://www.mrc-lmb.cam.ac.uk/. (B) A simplified, rooted tree depicting
the evolution of ADF-H domain proteins in mice. All three families of
ADF-H domain proteins were present in the common ancestor of yeast and
animals. Distinct members of the ADF/cofilin family in mouse arose
after the emergence of vertebrates. The asterisks denote our
predictions that destrin- and drebrin-like proteins will be found in
mouse, based on the phylogenetic tree shown in A. Protein names,
database, and accession numbers for the sequences, respectively, are
listed below. Where no database is stated, the accession number refers
to GenBank. S. cerevisiae cofilin: Swiss-Prot, Q03048;
S. pombe cofilin: DDBJ, D89939; D.
discoideum cofilin: Swiss-Prot, P54706; A.
castellanii actophorin: Swiss-Prot, P37167; A.
thaliana ADF1: U48938; A. thaliana ADF2: U48939;
L. longifolium ADF: PIR, S30935; Brassica
napus ADF: PIR, S30934; Z. mays ADF1:
Swiss-Prot, P46251; Z. mays ADF2: X97725; Z.
mays ADF3: X97726; Triticum aestivum cofilin:
U58278; Drosophila melanogaster ADF: PIR, A57569;
Caenorhabditis elegans ADF1: Swiss-Prot, Q07750;
C. elegans ADF2 (Swiss-Prot: Q07749), T.
gondii ADF: U62146; H. sapiens destrin
2:(U47924; H. sapiens destrin 1: PIR, A54184; S.
scrofa destrin: DDBJ, D90053; Gallus gallus ADF:
J02912; R. norvegicus cofilin: Swiss-Prot, P45592;
Mus musculus cofilin (nonmuscle isoform): Swiss-Prot,
P18760; H. sapiens cofilin: EMBL, X95404; S.
scrofa cofilin: M20866; G. gallus cofilin:
M55659; M. musculus cofilin (muscle isoform):
Swiss-Prot, P45591; X. laevis cofilin 1: U26270;
X. laevis cofilin 2: Swiss-Prot, P45593; M.
musculus twinfilin (repeat-1): U82324; H.
sapiens twinfilin (repeat-1): PIR, A55922; S.
cerevisiae twinfilin (repeat-1): SGD, YGR080W; M.
musculus twinfilin (repeat-2): U82324; H.
sapiens twinfilin (repeat-2): PIR, 55922; S.
cerevisiae twinfilin (repeat-2): SGD, YGR080W; H.
sapiens drebrin E: Swiss-Prot, Q16643; R.
norvegicus drebrin A: Swiss-Prot, Q07266; G.
gallus drebrin A, E1 and E2: Swiss-Prot, P18302; M.
musculus SH3P7: GenBank, U58884; D.
discoideum coactosin: Swiss-Prot, P34121; S.
cerevisiae Abp1: EMBL, X51780/Swiss-Prot, P15891; S.
exiguus Abp1: Swiss-Prot, P38479; A. amurensis
depactin: Swiss-Prot, P20690.