Expression of PINK1 in zebrafish D. rerio during development

PINK1 is a highly conserved 581 amino acid serine/threonine kinase that possesses an N-terminal mitochondrial targeting sequence. In spite of its predicted ubiquitous distribution, several evidence showed that the enzyme is present in discrete cell populations. In this study, we have investigated by Western blot analysis and immunohistochemistry the expression of PINK1 in the brain and eye of zebrafish during development. We detected two PINK1-positive bands in the whole zebrafish lysates: a smaller one, of 33 kDa, and a larger one, of 66 kDa, as early in zebrafish larvae at 48 hpf and throughout development up to 5-day larva. According with Western Blot analysis, PINK1-immunoreactivity appeared in the brain at 48 hpf. Immunoreactive cells were confined to some regions of the medulla oblongata and the hypothalamus. The expression was maintained also at later stage of development in 5-day larva in the same regions. At this stage a new expression domain appeared in the lens and in the retina of the eye and in the neuromasts of the lateral line. Outside the nervous system PINK1 was also expressed in the muscle and in the gut. In the developing nervous system a similar expression of PINK1 has been reported for comparable stages of mouse development. Our data showed a restricted expression pattern of PINK1 suggesting an involvement of this enzyme in developmental pathway linked to neuroregulatory mechanisms