title: A microarray analysis of the emergence of embryonic definitive hematopoiesis.
abstract: OBJECTIVE
  Human embryonic stem (ES) cells provide a unique model for studying the development and function of human tissues and have proven utility in a number of areas. However, results from ES cell-based studies have been limited by the paucity of information available about early human hematopoietic development.
  
  
  METHODS
  To better understand early development of the hematopoietic lineage, we use microarray analysis to examine the temporal patterns of gene expression in embryoid bodies derived from human ES cells, focusing around the time of the emergence of definitive hematopoiesis. We use an empirical Bayes hierarchical modeling approach, called EBarrays, to classify genes into each of the possible temporal patterns of gene expression for five different time points, and correlate those patterns with the emergence of hematopoiesis.
  
  
  RESULTS
  We find a distinct group of genes previously identified as important in adult hematopoietic self-renewal (such as PIK3R1, ABCB1/MDR-1, RGS18, IRS1, SENP6/SUMO-1, and Wnt5A, etc.) temporally correlates with the emergence of the definitive hematopoiesis. Microarray-based results are further supported via flow cytometry and reverse transcription-polymerase chain reaction studies.
  
  
  CONCLUSIONS
  The novel genes demonstrating the same expression pattern as this group could further facilitate the understanding of the molecular mechanisms of embryonic hematopoiesis.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Lewis
authors.forename: Christine A
authors.initials: CA
authors.lastname: Daigh
authors.forename: Coral
authors.initials: C
authors.lastname: Ho
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: James A
authors.initials: JA
authors.lastname: Thomson
authors.forename: Christina
authors.initials: C
authors.lastname: Kendziorski
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics*; D002460:Cell Line; D019070:Cell Lineage; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000737:chemistry / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D006410:Hematopoiesis / Q000235:genetics*; D006801:Humans; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D015854:Up-Regulation
chemical_list: D018952:Antigens, CD34