Genomic and physiological responses to strong selective pressure during late organogenesis: few gene expression changes found despite striking morphological differences

Table 1 Subset of embryogenesis-related genes whose expression significantly differs between reference (King’s Creek) and resistant (Elizabeth River) Fundulus heteroclitus embryos (Mixed model ANOVA, p < 0.01) during late organogenesis stage due to the effect of embryo morphology

Gene	Fold diff.	Effect	Ref
Cytochrome C oxidase iso-1/iso-2	1.51	Libman-Sacks endocarditis and antiphospholipid syndrome (aPLs)	[44, 45]
Complement factor H-related protein 2	1.43	Libman-Sacks endocarditis and antiphospholipid syndrome (aPLs)	[44, 45]
Myosin light chain (ELC / RLC)	1.94/1.3	Increase in cardiomyocyte size and number, resulting in a larger ventricular chamber volume/reduction in size and number of cardiomyocytes	[48, 49]
ATP synthase subunit S	1.47	Cellular ATP synthesis; depletion of the cellular ATP pool during ischemia	[46, 50]
GADD45 beta	1.56	Cell-cycle control; Somitogenesis abnormalities	[47]
Inositol polyphosphate multikinase (IPMK)	1.66	mRNA export, transcriptional regulation, and chromatin remodeling	[51]
Phosphatidylinositol phosphate kinase 4 (PIPK) beta	2.25	Mouse embryo brain expression (cerebral ventricular and mantle zones) during normal development; postnatal brain gray matter expression	[47]
Fumarate hydratase (fumarase)	1.77	Severe neurologic fetal brain abnormalities, poor feeding, failure to thrive; hypotonia, severe mental retardation, unusual facial features, brain malformation, epileptic seizures	[52, 53]

The expression pattern of genes for each morphology score group is presented in Figure 3b. While gene expression appears similar among embryos scored for no deformities (score 1), mild (score 2) and moderate (score 3), most differences in gene expression patterns are among severely deformed (score 4) and extremely deformed (score 5) embryos. Notably, all of the reference embryos co-exposed to ANF and BNF were either severely or extremely deformed, while none of the resistant embryos were found to be more than moderately deformed in any treatment.

ISSN: 1471-2164