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Table 1 The conserved motifs of PC homologues

From: Novel motifs distinguish multiple homologues of Polycomb in vertebrates: expansion and diversification of the epigenetic toolkit

Conserved motif

Present in

Size(aa)

Secondary structure

Function

Chromodomain

All

61

Twisted antiparallel β sheet (3 β strands and a helix)

Binds with H3K27me3

P olyc omb R epressor

(PcR) box

All

29-31

β strand

Interacts with dRING

AT-Hook

CBX2

29

Coils

DNA binding

AT-Hook Like

(ATHL)

CBX4, CBX6, CBX7 and CBX8

15

Coils

Present in several nuclear proteins (DNA binding?)

CX 2.1

CBX2

69-74

Coils

-

CX 2.2

CBX2

25

Coils

-

CX 4.1

CBX4

84-88

Coils

-

CX 4.2

CBX4

29

Coils

-

CX 4.3

CBX4

20

Coils

SUMO binding

CX 4.4

CBX4

31

Coils

-

CX 6.1

CBX6

82-88

Coils

-

CX 6.2

CBX6

36

Coils

-

CX 6.3

CBX6

15

Coils

-

CX 8.1

CBX8

39-42

Coils

-

Poly histidine site

Insect PC

CBX4 of mammals

6-11

10-14

Coils

-

RED repeat

CBX8 of mammals

13-37

Coils

Present in several proteins

CtBP interaction motif

CBX4

5

Coils

CtBP binding

Sumoylation site

CBX4 (Except fishes)

4-5

Coils

Sumoylation

Serine rich region

(SRR)

CBX2

CBX6

23-38

4-6

Coils

-

C onserved

I nsect Pc box

(CIPC)

Insect PC

25-29

Coils

Present in insect Polycomb

  1. The multiple sequence alignments of the conserved motifs are given in Additional file 5.