Differential gene expression during early murine yolk sac development

摘要: The visceral yolk sac (VYS), composed of extraembryonic mesoderm and endoderm, is the initial site blood cell development serves important nutritive absorptive functions. In mouse, endoderm becomes a morphologically distinct tissue at time implantation (E4.5), while arises during gastrulation (E6.5–8.5). To isolate genes differentially expressed in developing sac, polymerase chain reaction (PCR) methods were used to construct cDNA from late primitive streak neural plate stage (E7.5) murine VYS tissues. Differential screening led identification six mesoderm-enriched clones: ribosomal protein L13a, heat shock proteins hsc 70 hsp 86, guanine-nucleotide binding protein-related gene, cellular nucleic acid protein, a-enolase. One endoderm-specific was identified as apolipoprotein C2. situ hybridization studies confirmed differential expression these E7.5 These results indicate that representative populations can be obtained small numbers cells PCR methodologies permit study gene early mammalian postimplantation development. While all ubiquitously embryo proper, C2 confined endoderm. are consistent with hypothesis E7.5, provides differentiated liver-like functions, newly still largely undifferentiated tissue. © 1995 wiley-Liss, Inc.