The heart is the first organ to form and function during embryonic development. Improper heart growth can lead to congenital heart defects which are the most common type of developmental defects in humans. The two-chambered heart in a zebrafish embryo can be used to easily observe impacted heart formation. During the development of the embryo, retinoic acid (RA) is a regulator of heart formation. Imbalances of RA can create issues within the second phase of zebrafish heart formation during which the outflow tract (OFT) is formed. It is unknown, however, how RA specifically affects the OFT development during this second phase in zebrafish. N,N-diethylaminobenzaldehyde (DEAB) is a known RA pathway inhibitor and used to compare embryos against a control treatment of Dimethyl Sulfoxide (DMSO). We used a dilution series of DEAB and DMSO to treat the embryos from 24-72 hours post fertilization (hpf). The embryos were split to visualize the expression of the RA target cyp26a1 and elnb expression in smooth muscle of the OFT. As DEAB concentration was increased, the domain of elnb in the heart region increased. Furthermore, the results show a decrease in staining of cyp26a1 in regions of the eye and back of the head as the DEAB concentration increased. We also performed experiments to narrow down the time frame during which RA affects elnb expression, and found that the critical time window of activity is between 24 hpf and 50 hpf. Altogether, our results add insight to the mechanisms of RA signaling during outflow tract formation.
Author(s): Riley Johnson, Biology and Premedical Studies Major
Anna Medina, Biology Major
Advisor(s): Jennifer Schumacher, Department of Biology
You must be logged in to post a comment.