Table 1.

Deletion of N-terminal domains reduces dorsalizing activity of HyChdl in zebrafish embryos

mRNA	Picograms per embryo	n	Wild type, %	c1, %	c2, %	c3, %	c4, %
hychdl	150	85	28.2	38.8	20	11.8	1.2
hychdlΔIGFBP	150	196	45.5	38.3	13.3	3.1	0
hychdlΔFol	150	134	47.8	32.8	16.4	3	0
hychdlΔN	150	221	64.3	28.9	6.8	0	0

Embryos injected with hychdl mRNA exhibit strong dorsalization (c1–c4), whereas injection with N-terminally truncated hychdl constructs lacking the IGFBP (hychdlΔIGFBP), the follistatin (hychdlΔFol), or both domains (hychdlΔN) reveal reduced dorsalized or wild-type phenotypes.