title: Expression of Sara2 human gene in erythroid progenitors.
abstract: A human homologue of Sar1, named Sara2, was shown to be preferentially expressed during erythropoiesis in a culture stimulated by EPO. Previous studies, in yeast, have shown that secretion-associated and Ras-related protein (Sar1p) plays an essential role in protein transport from the endoplasmic reticulum to the Golgi apparatus. Here, we report the molecular analysis of Sara2 in erythroid cell culture. A 1250 bp long cDNA, encoding a 198 amino-acid protein very similar to Sar1 proteins from other organisms, was obtained. Furthermore, we also report a functional study of Sara2 with Real-time quantitative PCR analysis, demonstrating that expression of Sara2 mRNA increases during the initial stages of erythroid differentiation with EPO and that a two-fold increase in expression occurs following the addition of hydroxyurea (HU). In K562 cells, Sara2 mRNA was observed to have a constant expression and the addition of HU also up-regulated the expression in these cells. Our results suggest that Sara2 is an important gene in processes involving proliferation and differentiation and could be valuable for understanding the vesicular transport system during erythropoiesis.
authors.affiliation: State University of Campinas, Center of Hemotherapy and Hematology, Campinas, SP, 13083-970, Brazil.
authors.forename: Denis Leonardo Fontes
authors.initials: DL
authors.lastname: Jardim
authors.forename: Anderson Ferreira
authors.initials: AF
authors.lastname: da Cunha
authors.forename: Adriana da Silva Santos
authors.initials: Ada S
authors.lastname: Duarte
authors.forename: Camila Oresco
authors.initials: CO
authors.lastname: dos Santos
authors.forename: Sara Terezinha Olalla
authors.initials: ST
authors.lastname: Saad
authors.forename: Fernando Ferreira
authors.initials: FF
authors.lastname: Costa
mesh_terms: D000595:Amino Acid Sequence; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000502:physiology*; D004920:Erythropoiesis / Q000502:physiology*; D005784:Gene Amplification; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D020014:K562 Cells; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; C513282:SAR1B protein, human; D020559:Monomeric GTP-Binding Proteins; D006918:Hydroxyurea