Table 2. The TRANSFAC categorization of transcription factors (TFs)

 

TF categorization from TRANSFAC 6.0

 

 

Superclass

Class

Training matrices, n

Test alignments, n

1: Basic domains

1.1 : Leucine zipper factors (bZIP)

34

82

48

1.2 : Helix-loop-helix factors (bHLH)

13

1.3 : Helix-loop-helix/leucine zipper factors

22

1.4 : NF-1

6

1.5 : RF-X

1

1.6 : bHSH

6

2: Zinc-coordinating DNA-binding domains

2.1 : Cys4 zinc finger or nuclear receptor type

14

52

36

2.2 : Diverse Cys4 zinc fingers

13

2.3 : Cys2His2 zinc domain

21

2.4 : Cys5 cycteine-zinc cluster

3

2.5 : Zinc fingers of alternating composition

1

3: Helix-turn-helix

3.1 : Homeo domain

41

76

64

3.2 : Paired box

6

3.3 : Fork head / winged helix

4

3.4 : Heat shock factors

7

3.5 : Tryptophan clusters

17

3.6 : TEA domain

1

4: beta-scaffold factors

4.1 : RHR (Rel homology region)

15

60

13

4.2 : STAT

13

4.3 : p53

2

4.4 : MADs box

9

4.5 : b -Barrel a -helix TFs

1

4.6 : TATA-biding proteins

3

4.7 : HMG

5

4.8 : Heteromeric CCAAT factors

9

4.9 : Grainyhead

2

4.10: Cold-shock domain factors

0

4.11: Runt

1

0: Others TFs

...

...

1

 

For the training set, the counts are made on TFs that have >10 biologically identified binding sites; for the test set, TFs with at least 6 sites are counted.