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. 2006 Sep 25;26(24):9291–9301. doi: 10.1128/MCB.01183-06

FIG. 6.

FIG. 6.

XNS is expressed during early embryogenesis in proliferating tissues and its depletion affects the pattern of cell division and the expression of neuronal and neural crest markers. (A, part a) Expression of XNS during embryogenesis analyzed by RT-PCR. Control RT-PCR of histone H4 was used as a loading control. Note that XNS is expressed both maternally and zygotically. (A, parts b to i) Whole-mount in situ hybridization of XNS expression at the indicated stages Nieuwkoop-Faber stages (St) (27). (A, parts b and c) Dorsal views, anterior right. (A, parts d and i) Transversal sections at the indicated levels of the embryo shown in parts c and h, respectively. (A, parts e, f, and h) Lateral views, anterior right. (A, part g) Horizontal section of the embryo in part f at the level indicated. Note that XNS expression is first detected at the neurula stage in ectodermal cells of the sensorial layer, particularly around the anterior neural plate. At the tailbud and tadpole stages, XNS staining is observed in migratory cranial neural crests, the eye, and the otic vesicle. (i) Within the neural tube, XNS expression is restricted to the ventricular zone. np, neural plate; nc, neural crest; sle, sensorial layer of the ectoderm; ev, eye vesicle; s, somites; ov, otic vesicle; ba branchial arches. (B, part a) The XNS MO inhibits translation of XNS in vitro, whereas the XNSmis MO does not. (B, part b) Injection of the XNS MO, but not XNSmis, decreases the number of mitotic cells, as revealed using an antibody recognizing phosphorylated histone H3 (α-pH 3). Dorsal view of XNS MO- and XNSmis MO-injected embryos are shown. LacZ was coinjected as a lineage tracer. Control and injected sides revealed by LacZ staining are indicated (bottom panel). (d) Quantification of the results (percentage of pH 3-positive cells compared to control embryos). There is a significant difference between the percentages in control and MO NS-injected embryos by chi-square test (P = 0.002). n, number of cases analyzed. (C, parts a and d) XNS MO, but not XNSmis MO, decreases the expression of the indicated neuronal and neural crest markers at the neurula stage. The injected side is revealed by LacZ staining.