Figure 1.

Mammalian members of the Sp1-like/KLF family. (a) A phylogenetic tree of human Sp1-like/KLF proteins and mouse Sp5 and Sp6 (mSp5 and mSp6) identifies three general subgroups. Subgroup I consists of the proteins most highly related to Sp1 (Sp1-Sp6). The other Sp1-like/KLF proteins are divided into two additional groups (subgroups II and III). The tree was generated using Genetic Computer Group (GCG) sequence analysis software. (b) Sequence alignment of the zinc-finger domains of Sp1-like/KLF protein family members. The sequence of the zinc-finger motifs of human Sp1 was compared with the corresponding regions of previously identified human Sp1-like proteins and with mouse Sp5. The consensus zinc fingers (ZF1, ZF2 and ZF3) are indicated below the sequences and the amino-acid residues predicted to interact with DNA according to the Klevit model [58] are indicated by arrows. Identical residues are in black, similar residues in gray and different residues in lower case. The percentage similarity between the Sp1 and the other Sp1-like/KLF zinc-finger domains is indicated on the right. Note that the amino acids predicted to make contact with DNA within the first (KHA), second (RER) and third (RHK) zinc-finger domains of Sp1 are nearly identical to the corresponding regions of other members of the Sp1-like/KLF family. All sequences are available in the NCBI human genome database [57].