Developmental changes in the expression of sox2 in the zebrafish brain

Abstract

The family of B1 Sox transcription factors plays critical roles in the early stages of development, including the central nervous system. It was demonstrated that Sox2 is expressed in repressed neural stem cells. Therefore, we decided to investigate the expression of Sox2 in the brain of zebrafish at different ages to identify potential neurogenic areas, and to establish the developmental changes they undergo. The brains were assessed by qRT-PCR, western blot, and immunohistochemistry. The maximal expression of Sox2 was found at 15 dpf progressively decreases up to 30 dpf, then increases up to 40 dpf and remains unchanged up to 180 dpf. By western blot three protein bands of 28 kDa, 34 kDa (main band), and 38 kDa were detected in the brain of 180 dpf animals. The immunolocalization of Sox2 revealed that by 15 dpf Sox2 was detected in cells of the olfactory bulb, the walls of the telencephalic and diencephalic ventricles, several nucleus in the diencephalons, and the tectum opticum; by 25-50 dpf the Sox2 positive areas were the same as above, and in the rhombencephalic ventricle and cerebellum. In adult animals Sox2 was restricted to the olfactory bulb and to cells of the telencephalic ventricle walls. Taken together present results demonstrate that the potential neurogenic areas in the brain of zebrafish are widespread than in mammals and change with development, but they are primarily concentrated around the ventricles and olfactory bulb in adults, following a similar localization as in mammals.

Comparative expression patterns of Sox2 and Sox19 genes in the forebrain of developing and adult turbot (Scophthalmus maximus)

“…In the olfactory bulbs, Sm‐Sox2/19 expressing cells were observed in the ependymal layer of larval, juvenile, and adult turbot. Germanà et al () have described SOX2‐immunoreactive cells in the external and internal granular and cell layers of the olfactory bulbs in developing and adult zebrafish, which is at variance with our observations with in situ hybridization. These results may indicate the existence of important between‐species differences in teleosts, although the staining of three protein bands in western blots of zebrafish brain extracts (Germanà et al, ) also suggests that the antibody used by these authors reveals other unknown proteins.…”

“…Thus, Sm‐Sox2/19 expressing cells were located in a large periventricular stripe covering the medial, dorsal, and lateral ventricular zones of the everted dorsal telencephalon (pallium), and also in the ventricular side of the ventral and dorsal nuclei of the ventral telencephalon (subpallium). SOX2‐immunoreactive cells or Sox2 mRNA expressing cells have been observed along the dorsal and ventral telencephalic periventricular regions of developing and adult zebrafish (Adolf et al, ; Germanà et al, ; Lam, März, & Strähle, ; Lindsey et al, ; März et al, ). In adult zebrafish, prominent expression was reported in the subpallium and weak expression in Dm and ventricular regions of the pallium (“AGETAZ for Atlas of Gene Expression,” ; Diotel et al, ), while strong Sox19 expressing cells were observed mainly in the subpallial periventricular region corresponding to the rostral migratory stream and in other ventricular regions (“AGETAZ for Atlas of Gene Expression,” ; Diotel et al, ).…”

“…Moreover, in some teleosts Sox2 expression was reported in other tissues, such as, gonads, gills, and heart (Cui et al, ; Gao et al, ; Wei et al, ). SOX2 immunoreactive cells were found in the brain of developing and adult zebrafish in several periventricular areas considered as neurogenic zones (Adolf et al, ; Germanà et al, ; Grandel, Kaslin, Granz, Wenzel, & Brand, ; Lindsey, Darabie, & Tropepe, ; März et al, ; Pellegrini et al, ; Schmidt, Strähle, & Scholpp, ; Zupanc, Hinsch, & Gage, ). So, Sox2 appears involved in the maintenance of pluripotency and neurogenesis, which in teleosts occurs throughout life (reviewed in Chapouton, Jagasia, & Bally‐Cuif, ; Ganz & Brand, ; Zupanc & Sîrbulescu, ).…”

TRPV4 in the sensory organs of adult zebrafish

“…To characterize the antibodies used in the study, we used Western blots of lysates prepared from head homogenates following procedures previously described (Germanà et al,2010). Briefly, the samples were pooled and homogenized (1:2, wt/vol) in Tris‐HCl buffered saline (TBS, 0.1 M, pH 7.5) containing 1 μM leupeptin, 10 μM pepstatin, and 2 mM phenylmethylsulfonyl fluoride.…”

Efficient homologous recombination-mediated genome engineering in zebrafish using TALE nucleases

“…We used rabbit anti-Sox10 [a gift from Dr Bruce Appel (University of Colorado School of Medicine, Aurora, CO, USA); 1:3000] (Park et al, 2005), mouse anti-HuC/D (Invitrogen, 16A11; 1:200) and mouse anti-GFAP (Sigma, G-A-5; 1:200) as primary antibodies, and anti-rabbit and anti-mouse IgG antibodies conjugated with Alexa Fluor 488, 568 and 647 (Invitrogen, A11001, A11011, A21237; 1:200) as secondary antibodies. Although we tried to test whether sfGFP-positive cells express Sox2 by immunohistochemistry using two different Sox2 antibodies that were previously reported to detect Sox2 in zebrafish (Germana et al, 2011;Hernandez et al, 2007), we failed to detect endogenous Sox2. The fluorescence imaging was carried out using Quorum Spinning disc Confocal/IX81-inverted microscope (Olympus) and Metamorph Acquisition software.…”