?Wnt signaling: Is the party in the nucleus? Genes Dev. Mouse monoclonal to RICTOR 20: 1394C1404. THE primitive embryonic gonad in is composed of two distinct cell types, the germ cells and the somatic gonadal precursor cells (SGPs) (Santos and Lehmann 2004). These two cell types are formed at different locations in the embryo and are specified by Corticotropin Releasing Factor, bovine distinct mechanisms. The germ cells arise as pole cells at the posterior end of the precellular blastoderm embryo, and their Corticotropin Releasing Factor, bovine proper specification depends on maternal determinants that are assembled in the pole plasm during oogenesis. After cellularization of the blastoderm, the germ cells must make their way into the center of the embryo and then migrate toward the newly formed SGPs in parasegments (PS) 10C13. SGPs are derived from dorsolateral mesodermal tissue in these parasegments and are specified by the hierarchical action of zygotic patterning genes. The dorsolateral mesoderm of PS 10C13 is usually formed under the control of and (Moore 1998) while the eventual specification of SGPs from these cells depends upon the bifunctional transcription factor (1997; Moore 1998). Although is required for SGP identity, it is differentially expressed in anterior and posterior SGPs. This difference depends upon the activity of the homeotic genes ((and (Boyle and DiNardo 1995; De Falco 2004). In addition to differences between anterior and posterior SGPs, the embryonic gonad is usually sexually dimorphic. One sex-specific difference is in the activity of signaling pathways that mediate communication between the SGPs and the primordial germ cells (PGCs). Wawersik (2005) found that the ligand for the JAK-STAT pathway, (2003), is usually expressed in a small group of SGPs at that very anterior of the embryonic gonad in male but not female embryos. [The same sex-specific expression pattern is seen for the closely related (Hombria 2005).] The ligand signals to the germ cells in male embryos upregulating the level and activity of the transcription factor STAT92E (Hou 1996). By contrast, there is little, if any, STAT92E in the germ cells of female embryos. The activity of the JAK-STAT pathway in males and females is dependent upon the somatic sex determination pathway. The sex determination pathway can be bypassed in females by ectopic expression of (or or 2003, 2008). One example of a cell type found only in males is the pigment precursor cell. These cells arise late in embryogenesis and are distributed around the outside of the embryonic gonad. Their specification depends upon the ligand gene. Another sex-specific cell type is the male-specific SGP (msSGP), which is clustered at the posterior end of the coalesced gonad. msSGPs are specified by a mechanism that seems to be impartial Corticotropin Releasing Factor, bovine of and ligand, and the transcription factor Sox100B. While Sox100B protein is usually detected only in the male gonads, expression is usually observed in gonads of both sexes around the time that this germ cells and SGPs first make contact. Subsequently, at the gonad coalescence stage, is usually greatly enriched in the male gonads in the msSGPs (De Falco 2003). At this stage another SGP-specific marker, Eya, is also enriched in msSGPs. Although msSGPs are found only in the coalesced gonads of male embryos, their initial specification is not sex specific. Thus, Sox100B/Abd-B-positive cells are detected in PS 13 of both male and female stage 13 embryos. However, survival of msSGPs is usually controlled by the (2003). In the studies reported here we have examined the role of in the development of the male gonad. We show that promotes survival of.