Selecting And Identifying Tiny RNA From K562 Cells And Hel Cells Before Or After Them Induced To Expreess Hemoglobin Genes

Because molecular disease of hemoglobin is world widely, incidence rate highly and very hazardous, or perhaps because blood samples are readily available, globin research has always been on the leading edge of the biomedical sciences, appealing not only to hematologists but also to many scientists working in the related fields of genetics, structural biology, and molecular biology. The convergence of different scientific disciplines and leading scientists in one field has stimulated research and led to impressive advances in our scientific knowledge over the years. In fact, many of the most exciting biomedical discoveries in the 20th century are linked to globin research. Beta-thalassemia is one of most hazardous hemoglobin disease, but increasing the expression gamma-globin gene can ameliorate it. Much study has been carried out to make out how to hold back the switching from gamma-globin to beta-globin, or how to reactivate the expression of gamma-globin gene. A lot of trans-acting-factor and cis-acting element have been identified. Some drugs, such as hydroxyurea and butyrate, are potent inducers of gamma-globin mRNA accumulation and fetal hemoglobin (HbF) production in erythroid cells from human normal subjects and beta-thalassemia patients. They were able to up regulate preferentially gamma-globin mRNA production and to increase HbF accumulation, percentage of HbF-containing cells and their HbF content. But they are transient, variable, and unpredictable. It's known now that HbF induction by hydroxyurea is mediated by the NO-dependent activation of sGC. Then cGMP is increased. cGMP could potentially affect gamma-globin expression through Spl or related transcription factors, as well as through AP-1. Butyrate not only inhibits histone deacetylase but also affect the binding of transcription factors with BREs. Butyrate-induced erythroid differentia -tion of human K562 leukemia cells involves inhibition of ERK and activation of p38 MAP kinase pathways. Butyrate may also increase cGMP in the cell.It's not until these years tiny RNA is becoming recognized. Tiny RNA is one member of noncoding RNAs. Noncoding RNAs (ncRNAs) are a number of RNAs that do not function as messenger RNAs (mRNAs), transfer RNAs (tRNAs), or ribosomal RNAs (rRNAs). They have been found to have roles in a great variety of processes, including transcriptional regulation, chromosome replication, RNA processing and modification, messenger RNA stability and translation, and even protein degradation andtranslocation.In animals, double-stranded short interfering RNA (siRNA) and single-stranded microRNA (miRNA) regulate gene expression by targeting homologous mRNA for cleavage or by interfering with their translation, respectively. miRNAs probably inhibit translation of mRNAs via imprecise antisense base-pairing. Small interfering RNAs (siRNAs) are similar in size to miRNAs, but they recognize targets by precise complementarity and elicit RNA-mediated interference (RNAi). Based on the evolutionary conservation of many miRNAs among the different animal lineages, it is reasonable to suspect that some mammalian miRNAs might also have important functions during development. Three miRNAs have been identified that are specifically expressed in mouse hematopoietic cells and show that their expression is dynamically regulated during early hematopoiesis and lineage commitment. This indicates that microRNAs are components of the molecular circuitry that controls mouse hematopoiesis and suggest that other microRNAs have similar regulatory roles during other facets of vertebrate development. But no conclusion is found if there is any relation between miRNA and gamma-globin expression induced by drugs.Is there any miRNAs taking part in the course of erythroid differentiation of human K562 leukemia cells induced by butyrate or hydroxyurea? Hydroxyurea may induce beta-globin gene expression in HEL, but no beta-globin chain is detected. It's just like the phenomenon of post-transcription gene silencing. Is any miRNA responsible for it? We will try to select ti...