Table 2

Presence of E. coli K12 transcription factors in close and remote relatives

TF type
In E. coli K12
Entero-absent*
Entero- present
Widely present

All TFs
143
65 (45.5%)
65 (45.5%)
13 (9%)







TFs that regulate ≤ 5 targets

     All
71
34 (48%)
35 (49%)
2 (3%)
     Activators
39
22 (56%)
16 (41%)
1 (3%)
     Repressors
27
11 (41%)
15 (56%)
1 (3%)
     Dual regulators
5
1 (20%)
4 (80%)
0 (0%)







TFs that regulate >5 targets

     All
72
31 (43%)
30 (42%)
11 (15%)
     Activators§
29
21 (72%)
7 (24%)
1 (4%)
     Repressors
22
7 (32%)
13 (59%)
2 (9%)
     Dual regulators¥
21
3 (14%)
10 (48%)
8 (38%)

*Absent from Enterobacteriaceae. Present in Enterobacteriaceae but absent from other γ-proteobacteria. Present in most γ-proteobacteria. §TFs are included in this group if they activate more than five targets. If the same TF also represses targets (dual regulator), it is included in this group only if the number of targets it activates is more than twice the number of repressed targets, and if the number of repressed targets is not larger than five. TFs are included in this group if they repress more than five targets. If the TF is a dual regulator, it is included in this group only if the number of targets it represses is more than twice the number of activated targets, and if the number of activated targets is not larger than five. ¥TFs are included in this group if they regulate more than five genes but cannot be assigned to the previous two groups.

Hershberg and Margalit Genome Biology 2006 7:R62   doi:10.1186/gb-2006-7-7-r62