. 2020 Oct 26;11(11):1262. doi: 10.3390/genes11111262

Table 2.

Classification of bHLH genes in the ascidian Ciona robusta. Modified from [147,148].

Phylogenetic Group	Characteristics	C. robusta bHLH Genes
A	Bind to CAGCTG or CACCTG	Ascl.a, Ascl.b, Ascl.c , Atoh8 , Atonal, Bhlha15, Hand, Hand-r , Mesp, Mrf, Neurog , Ptf1a , Ptf1a-r , Tcf3 , Tcf15-r, Twist-r.a, Twist-r.b, Twist-r.c*
B	Bind to CACGTG or CATGTTG	AP4, Figla-r ^#, Mad , Max, Mitf , Mlx, Mnt-r , Myc , Srebp , Usf *
C	Bind to ACGTG or GCGTG. Contain a PAS domain	AHR, ARNT, Hif , Sim ^#, Trh*
D	Lack basic domain and do not bind to DNA. Act as antagonists of group A bHLH proteins	Id.a ^#, Id.b *
E	Contain an orange domain and a WRPW peptide	Hes.a , Hes.b , Hes.c, Hey
F	Contain an additional COE domain, which is involved in dimerization and DNA binding	Ebf *
Outgroup		Bhlh-tun1 , Bhlh-tun2 , Bhlh-tun3 ^#, Bhlh-tun4 Uncertain classification: bHLH-like1 ^#

* Genes that are expressed in the sensory vesicle territory at the mid/late tailbud stage and/or in the adult neural complex, as determined by whole-mount in situ hybridization. ^# Genes without published whole-mount in situ hybridization data.