Table 3.

Effects of genetic or pharmacological treatments on laterality and the degree of repair of incorrect laterality, calculated as the percentage of embryos with incorrect Nodal expression that have correct organ situs, using separate clutches for each analysis. H7: gap junction communication disruptor. Lansoprazole: blocker of H+/K+-ATPase pump; ropisetron: serotonin receptor blocker; anandamide: gap junction communication blocker; heptanol: gap junction communication blocker; glycyrrhetinic acid: gap junction communication blocker. R: right; Bi: bilateral; N: none (correct sidedness is Left). A positive degree of repair indicates that embryos with incorrect gene expression went on to have normal organ situs, indicating that some defects in expression of early laterality markers are being corrected by the time of organ placement. A negative degree of repair indicates that early errors are amplified by subsequent steps.

treatmentincorrect Nodal expressionincorrect Lefty expressionincorrect Pitx2 expressionreversed organsreferencesdegree of repair
protein misexpression
Cx26 2 of 4-cell: ventral48%
(R: 1%, Bi: 1%, N: 46%)
n = 109
32%
n = 150
[166]33%
Cx43 2 of 4-cell: ventral32%
(R: 0%, Bi: 5%, N: 27%)
n = 78
22%
n = 149
[166]31%
H7 2 of 4-cell: dorsal57%
(R: 5%, Bi: 14%, N: 38%)
n = 42
29%
n = 173
[166]49%
drug treatment
lansoprazole36%
(R: 18%, Bi: 7%, N: 11%)
n = 28
40%
(R: 4%, Bi: 32%, N: 4%)
n = 25
47%
(R: 23%, Bi: 18%, N: 6%)
n = 34
51%
n = 88
[80]−42%
tropisetron36%
(R: 6%, Bi: 15%, N: 15%)
n = 153
16%
(R: 2%, Bi: 5%, N: 9%)
n = 174
23%
n = 420
[144]36%
anandamide53%
(R: 1%, Bi: 3%, N: 49%)
n = 73
35%
n = 223
[166]34%
heptanol81%
(R: 0%, Bi: 0%, N: 81%)
n = 37
48%
n = 283
[166]41%
glycyrrhetinic acid90%
(R: 2%, Bi: 2%, N: 86%)
n = 59
40%
n = 290
[166]55%