Neuroanatomical demonstration of calbindin 2a- and calbindin 2b-like calcium binding proteins in the early embryonic development of zebrafish: mRNA study.

Certain calcium binding proteins (CaBPs) are essential for metabolic processes but the role of these proteins in the development is not well known. We have investigated the mRNA expression of CaBPs, calbindin 2a (Calb2a) and calbindin 2b (Calb2b) in the zebrafish embryos 24, 36, 48 and 72h post fertilization (hpf). We have seen very high Calb2a mRNA expression in the tegmentum (Tg), midbrain-hindbrain boundary (Mhb), hindbrain (Hb), spinal cord (Sc), retina and cranial ganglion (Crg). Also very high Calb2b mRNA expression was noted in olfactory cells, cerebellum, Tg, Mhb, Hb, optic tectum, retina, retinal ganglion cell layer, retinal inner nuclear layer, Sc, Neural crest, infraorbital neuromasts, pharyngeal arch 3-7 skeleton and mandibular neuromasts. It is known that many factors are involved in the differentiation of Mhb. Here we are reporting for the first time the mRNA expression of CaBPs (Calb2a and Calb2b) in the Mhb indicating their role in the differentiation of Mhb and development of the brain, eyes and other tissues in the zebrafish. We suggest that Calb2a and Calb2b play an important role in the regulation of zebrafish early embryonic development.