Background The embryonic developmental process in avian species is quite different from that in mammals. for 32 genes at developmental four points; stage X (0 h), HH stage 3 (12 h), HH stage 6 (24 h), and HH stage 9 (30 h). Additionally, we further analyzed four genes with less than twofold expression increase at HH stage 3. As a result, we identified a set of stage-specific genes during the early chick embryo development; 21 genes were relatively up-regulated in the stage X embryo and 12 genes were relatively up-regulated in the HH stage 3 embryo based on both results of microarray and quantitative RT-PCR. 54-62-6 manufacture Conclusion We identified 54-62-6 manufacture a set of genes with stage-specific expression from microarray Genechip and quantitative RT-PCR. Discovering stage-specific genes will aid in uncovering the molecular mechanisms involved the formation of the three germ layers and germ cell segregation in the early chick embryos. Background In embryogenesis, a series of developmental events begins immediately after fertilization. During the early embryo development, the expression of many genes is spatiotemporally triggered or suppressed, under tight transcriptional control. However, the intricate changes in gene expression in the early embryo have yet to be investigated in detail in mammals or birds. As avian species are oviparous, the embryo is readily accessible even at the earliest stages and can effectively be manipulated for purposes including profiling the genes expressed in embryogenesis. Recently, the chicken genome was 54-62-6 manufacture completely sequenced , and furthermore, Burt et al  reported that the 54-62-6 manufacture organization of the human genome is actually closer to that of the chicken than the mouse. Thus, the chicken is an interesting and relevant experimental animal model. In avian species, the embryonic developmental process is quite different from that in mammals. The first cleavage begins 4 h after fertilization, as the embryos enter the magnum of the reproductive duct , but the first differentiation does not occur until the egg is laid. Cells in the embryo continue to proliferate until the Eyal-Giladi and Kochav stage X and the laid egg consists of 40,000 to 60,000 undifferentiated embryonic cells . After 12 to 13 h of incubation at Hamburger and Hamilton (HH) stage 3, the primitive streak extends to about the center of the area pellucida . The groove in the primitive streak is gradually established as the cells of surrounding epiblast rapidly divide and migrate to the lower regions of the embryo, where they spread laterally across the surface of the yolk into two layers, the endoderm and mesoderm. Together with when the three germ layers begin to form, the first appearance of germ cells is an important event during the early embryo development. Primordial germ cells, the progenitors of sperm or egg cells after sexual maturity, first appear from the epiblast in the blastoderm at stage X and translocate to the hypoblast of the area pellucida [6-8]. During gastrulation, they circulate through the vascular system and finally settle in the gonadal anlagen . Understanding the molecular mechanisms that underlie germ cell segregation during early embryogenesis is important not only from the perspective of fundamental research in embryology but also from that of practical use of genetic methods. Additionally, discovering developmental stage-specific genes will aid in uncovering the molecular mechanism involved in the early stages of chicken embryo development. In this study, we investigated the linkage of gene expression with morphological events, including germ cell segregation and identified gene transcripts from microarray GeneChip technology (stage X versus HH stage 3). We further analyzed our gene expression data using quantitative RT-PCR. Results Microarray data analysis Microarray analyses were conducted to identify genes that were differentially expressed between Eyal-Giladi and Kochav stage X and Hamburger and Hamilton (HH) stages 3 embryos. Raw expression levels were corrected and normalized using the RMA function and the affy 54-62-6 manufacture software. Rabbit polyclonal to CREB.This gene encodes a transcription factor that is a member of the leucine zipper family of DNA binding proteins.This protein binds as a homodimer to the cAMP-responsive element, an octameric palindrome. A correlation matrix showed that the between-group variances were higher than the within-group variances (Figure ?(Figure1).1). Hierarchical clustering was conducted upon all probes by using Cluster, and the clustering result was displayed using TreeView software (Figure ?(Figure22). Figure 1 Plot of correlation matrix between all pairs. The ellipse represents a.