Essential roles of a zebrafishprdm1/blimp1homolog in embryo patterning and organogenesis

Abstract

formation of dorsoanterior structures and reduces expression of chordin, which encodes a BMP antagonist. Conversely, interference with Prdm1 translation using antisense morpholino oligonucleotides, increases chordin expression, while reducing expression of Bmp genes, and consequently dorsalizing the embryo. At the end of the gastrula period, prdm1 morphant embryos have enlarged animal-vegetal and anteroposterior embryonic axes. This altered embryo morphology is associated with augmented extension movements of dorsal tissues and normal posterior migration of ventral tissues. Additionally, Prdm1 activity is essential for proper development of slow muscle, the photoreceptor cell layer, branchial arches and pectoral fins. Our studies reveal essential roles for prdm1 in limiting the function of the gastrula organizer and regulating cell fate specification and morphogenetic processes in precise correspondence with its intricate expression pattern.

Identification and expression profiles of prdm1 in medaka Oryzias latipes

“…Bar, 100 lm ectoderm such as the eye, prechordal plate, otic vesicles and tail of the embryos. This expression pattern is similar to that of mouse prdm1 [37] and zebrafish prdm1a [41,46]. However, no observation of prdm1a was in the primordial germ cells (PGCs) of medaka.…”

“…However, no observation of prdm1a was in the primordial germ cells (PGCs) of medaka. These results hinted that medaka Prdm1a possibly has similar function as its homologues of zebrafish and mouse in development of muscle [38,46], neural crest [41,46], branchial arches [46], fin [43,44,46], eye [29,55], intestine [30,31], heart [28] and bone [56]. In mouse, Prdm1 plays its role itself and/or through its partner factors, Prmt5 and/or Groucho proteins [9,25].…”

“…Zebrafish prdm1a is expressed in the visceral endoderm, anterior endomesoderm and the prechordal plate of gastrula stage embryos, and is expressed in pharyngeal arches, limb buds, otic vesicles, photoreceptor cell layer, slow muscle and cloaca later in development [41]. Prdm1a plays major roles in dorsal-ventral patterning in zebrafish embryos [41] and is required for specification of the slow-twitch muscle lineage [38,42], branchial arches [41], pectoral fin [41,43,44], neural crest and sensory neuron progenitors [45,46] in zebrafish. However, the role of Prdm1 in fish immune system is still elusive.…”

Blimp1 and the Emergence of the Germ Line during Development in the Mouse

“…38,39 In the Xenopus and zebrafish, Blimp1 is expressed in the anterior mesendoderm and prechordal plate, where it is required for regulating appropriate functions of these tissues. 40,41 Notably, as stated above, germ cell specification in Xenopus and zebrafish is predetermined by the inheritance of germ plasm, and consequently, no defects in germ cell formation have been reported in these organisms in the absence of Blimp1. In mice, Blimp1 is expressed in the analogous anterior visceral endoderm (AVE) and anterior definitive endoderm (ADE)/prechordal plate.…”

Epidermal terminal differentiation depends on B lymphocyte-induced maturation protein-1

“…It is required at various stages of early embryonic development in Drosophila melaganoster (4), Xenopus laevis (5), zebrafish (6,7), and mice (8). In adult mice, it is best characterized in lymphocytes where it is required and sufficient for terminal differentiation of B cells to plasma cells (9).…”