PgmNr Z6070: The regulatory subunits of calcineurin differentially direct zebrafish brain development.

Authors:
Robert Thorn; Danielle Clift; Robbert Creton


Institutes
Brown University, Providence, RI.


Abstract:

Calcineurin, a serine/threonine phosphatase that is integral for immune function has been a target for immunosuppressant drugs for decades. Use of calcineurin inhibition drugs during pregnancy is of particular concern since little is known about the effects of cyclosporine during brain development. We have previously shown that exposing zebrafish embryos to cyclosporine, a calcineurin inhibitor, has led to decreased brain size in larval zebrafish. The current studies have examined the specific role of calcineurin in the developing zebrafish brain. Zebrafish embryos were injected with varying levels of morpholinos against one of the two regulatory subunits of calcineurin (ppp3r1a or ppp3r1b). Brain sizes were assessed at 3 days post fertilization (dpf) and behavioral tests were performed at 5 dpf. At ‘medium’ injection levels the ppp3r1a morpholino showed a decrease in all measured brain regions, the ppp3r1b morpholino injected embryos showed only a decrease in the midbrain size. In addition, we found a significant decrease in zebrafish brain size when embryos were injected with ‘low’ levels of both morpholinos together, but separate injections of each morpholino showed no difference at these levels. ‘Low’ injection embryos underwent behavioral testing and showed abnormal social behavior in the ppp3r1a and ppp3r1b injected larvae. Additionally, ppp3r1b injected larvae were hypoactive compared to controls and ppp3r1a injected, while the ppp3r1a exhibited less thigmotaxis behavior compared to the controls and the ppp3r1b injected larvae. These results suggest an integral role of calcineurin during early brain development in zebrafish. The results also suggest that the calcineurin regulatory subunits have different roles in behavioral development during early zebrafish development.



ZFIN Genetics Index
1. ppp3r1a
2. ppp3r1b