Abstract
Purpose: :
The scinderin-like a (scinla) gene (previously called C/L-gelsolin) encodes 50% of the water-soluble protein of the zebrafish cornea and is known as a corneal crystallin. Phylogenetic analysis led to the discovery of scinlb, a duplicate of scinla. scinlb is expressed to a lesser extent than scinla in the cornea. Here we compare the expression patterns and functions of scinla and scinlb during development.
Methods: :
Digoxigenin-UTP labeled RNA probes (~500 bp) were generated by in vitro transcription and used for whole mount in situ hybridization. Translation blocking and mRNA splice disrupting morpholino antisense oligonucleotides (MO) were microinjected into the yolk in 1-2 cell embryos. Histology was performed by conventional methods.
Results: :
scinla and scinlb, located on chromosomes 6 and 2, are 71% identical at the protein level. Our previous experiments (Kanungo et al. Proc. Natl. Acad. Sci. USA 100: 3287-3292, 2003) showed that scinla is expressed slightly during cleavage stages and principally in the cornea and lens during zebrafish development. Interference of scinla expression by specific MO experiments ventralizes the embryos. By contrast, we show here that scinlb is expressed in the floor plate, hatching gland, brain (mainly in the ventricular region) and small subset of hematopoietic cells at one day postfertilization. No expression was detected in the eye by 48 hours postfertilization. MO experiments interfering with scinlb expression caused a brain phenotype with multiple apoptotic cells throughout by 24 hours postfertilization. The embryos did not die, however, as judged by their ability to continue development.
Conclusions: :
The duplicate scinla and scinlb genes have entirely different expression patterns and functions during zebrafish development.
Keywords: gene/expression • development