Table 1 Gene expression and activities of upregulated chromatin remodeler genes and transcription factors in elapid and viperid milked venom glands

Chromatin remodeler genes

Elapid 96 hpvm

Viperids 96 hpvm

Activity

SRCAP

86-fold

C. viridis:

3-fold

C. tigris:

12-fold

A coactivator for several TFs (CREB, the glucocorticoid receptor and the androgen receptor), and functions by exchanging nucleosome histones to render DNA accessible for transcription [77,78,79].

JMJD1C

43-fold

C. viridis:

N.C.

C. tigris:

3-fold

Alters chromatin accessibility by histone demethylation, activating transcription [80].

KMT2A, KMT2C, and KMT2D

80-, 45-, and 64-fold

C. viridis:

1-, N.C., and 2-fold

C. tigris:

2-, 24-, and 18-fold

Methylate lysine 4 of histone 3 (H3), a tag for epigenetic transcriptional activation [81,82,83].

CHD8

52-fold

C. viridis:

N.C.

C. tigris:

5-fold

Interacts with H3 di- and tri-methylated at lysine 4, recruiting histone H1 and repressing genes regulated by β-catenin (Wnt signaling pathway) [84,85,86].

Transcription factor genes

Activity

SP1

79-fold

C. viridis:

4-fold

C. tigris:

5-fold

Binds GC box and related GT/CACC box regulatory elements in promoter, enhancer and locus control regions of housekeeping and tissue-specific genes [87].

FOXN2

41-fold

C. viridis:

N.C.

C. tigris:

12-fold

Binds purine-rich regions and members of this TF family have been implicated as regulators of embryogenesis, cell cycling, and cell lineage restriction [88].

LCOR

40-fold

C. viridis:

N.A.

C. tigris:

2-fold

Can function as either a transcription activator or repressor and has been linked to polycomb-group target genes, promoting methyltransferase activity [89, 90].

CREB3L3

N.C.

C. viridis:

11-fold

C. tigris:

N.A.

TF involved in ER stress and activating the unfolded protein response [91].

NFIA, NFIB, and NFIX

17-, 5-, and

17-fold

C. viridis:

5-, 6-fold, and N.C.

C. tigris:

31-, 133-, and 24-fold

NFI family of TFs regulates genes across many different cell types, recognizing a palindromic consensus DNA sequence TGGA/C(N)₅GCCAA [92].