Anti-IgM induces up-regulation and tyrosine-phosphorylation of heterogeneous nuclear ribonucleoprotein K proteins (hnRNP K) in a Ramos B cell line

2005 ◽  
Vol 98 (2) ◽  
pp. 303-310 ◽  
Author(s):  
Hye-Kyung Jeon ◽  
Jeong-Hun Ahn ◽  
Jongseon Choe ◽  
Jeon Han Park ◽  
Tae H. Lee
Keyword(s):  
B Cell ◽  
Cell Line ◽  
Tyrosine Phosphorylation ◽  
Hnrnp K ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Nuclear Ribonucleoprotein

scholarly journals Heterogeneous nuclear ribonucleoprotein K is a transcription factor.

1996 ◽  
Vol 16 (5) ◽  
pp. 2350-2360 ◽  
Author(s):  
E F Michelotti ◽  
G A Michelotti ◽  
A I Aronsohn ◽  
D Levens
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Hnrnp K ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Transcription In Vitro ◽  
Nuclear Ribonucleoprotein ◽  
Rna Polymerase Ii Transcription

The CT element is a positively acting homopyrimidine tract upstream of the c-myc gene to which the well-characterized transcription factor Spl and heterogeneous nuclear ribonucleoprotein (hnRNP) K, a less well-characterized protein associated with hnRNP complexes, have previously been shown to bind. The present work demonstrates that both of these molecules contribute to CT element-activated transcription in vitro. The pyrimidine-rich strand of the CT element both bound to hnRNP K and competitively inhibited transcription in vitro, suggesting a role for hnRNP K in activating transcription through this single-stranded sequence. Direct addition of recombinant hnRNP K to reaction mixtures programmed with templates bearing single-stranded CT elements increased specific RNA synthesis. If hnRNP K is a transcription factor, then interactions with the RNA polymerase II transcription apparatus are predicted. Affinity columns charged with recombinant hnRNP K specifically bind a component(s) necessary for transcription activation. The depleted factors were biochemically complemented by a crude TFIID phosphocellulose fraction, indicating that hnRNP K might interact with the TATA-binding protein (TBP)-TBP-associated factor complex. Coimmunoprecipitation of a complex formed in vivo between hnRNP K and epitope-tagged TBP as well as binding in vitro between recombinant proteins demonstrated a protein-protein interaction between TBP and hnRNP K. Furthermore, when the two proteins were overexpressed in vivo, transcription from a CT element-dependent reporter was synergistically activated. These data indicate that hnRNP K binds to a specific cis element, interacts with the RNA polymerase II transcription machinery, and stimulates transcription and thus has all of the properties of a transcription factor.

scholarly journals Heterogeneous nuclear ribonucleoprotein K represses transcription from a cytosine/thymidine-rich element in the osteocalcin promoter

2005 ◽  
Vol 385 (2) ◽  
pp. 613-623 ◽  
Author(s):  
Joseph P. STAINS ◽  
Fernando LECANDA ◽  
Dwight A. TOWLER ◽  
Roberto CIVITELLI
Keyword(s):  
Gene Transcription ◽  
Nuclear Extract ◽  
Binding Activity ◽  
Proximal Promoter ◽  
Luciferase Reporter ◽  
Mobility Shift ◽  
Hnrnp K ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Osteocalcin Gene ◽  
Nuclear Ribonucleoprotein

HnRNP K (heterogeneous nuclear ribonucleoprotein K) was biochemically purified from a screen of proteins co-purifying with binding activity to the osteocalcin promoter. We identify hnRNP K as a novel repressor of osteocalcin gene transcription. Overexpression of hnRNP K lowers the expression of osteocalcin mRNA by 5-fold. Furthermore, luciferase reporter assays demonstrate that overexpression of hnRNP K represses osteocalcin transcription from a CT (cytosine/thymidine)-rich element in the proximal promoter. Electrophoretic mobility-shift analysis reveals that recombinant hnRNP K binds to the CT-rich element, but binds ss (single-stranded), rather than ds (double-stranded) oligonucleotide probes. Accordingly, hnRNP K antibody can supershift a binding activity present in nuclear extracts using ss sense, but not antisense or ds oligonucleotides corresponding to the CT-rich −95 to −47 osteocalcin promoter. Importantly, addition of recombinant hnRNP K to ROS 17/2.8 nuclear extract disrupts formation of a DNA–protein complex on ds CT element oligonucleotides. This action is mutually exclusive with hnRNP K's ability to bind ss DNA. These results demonstrate that hnRNPK, although co-purified with a dsDNA-binding activity, does not itself bind dsDNA. Rather, hnRNP K represses osteocalcin gene transcription by inhibiting the formation of a transcriptional complex on the CT element of the osteocalcin promoter.

scholarly journals Retroviral insertions downstream of the heterogeneous nuclear ribonucleoprotein A1 gene in erythroleukemia cells: evidence that A1 is not essential for cell growth.

1992 ◽  
Vol 12 (10) ◽  
pp. 4449-4455 ◽  
Author(s):  
Y Ben-David ◽  
M R Bani ◽  
B Chabot ◽  
A De Koven ◽  
A Bernstein
Keyword(s):  
Cell Growth ◽  
Cell Line ◽  
Rna Splicing ◽  
Rna Binding ◽  
Leukemia Virus ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Friend Leukemia ◽  
Erythroleukemia Cell ◽  
Nuclear Ribonucleoprotein ◽  
Friend Leukemia Virus

A large number of novel cellular proto-oncogenes have been identified and cloned by analysis of common integration sites in retrovirally induced malignancies. In the multistage erythroleukemias induced by the various strains of Friend leukemia virus, the analysis of proviral-integration events has led to the identification of two genes, Fli-1 and Spi-1, both novel members of the ets oncogene family of transcription factors. In this report, we describe the identification of another integration site, designated Fli-2 (Friend leukemia virus integration-2), in an erythroleukemia cell line induced by Friend murine leukemia virus (F-MuLV). Rearrangements at the Fli-2 locus were found in two erythroleukemia cell lines independently induced by F-MuLV and one leukemic cell line derived from the spleen of a mouse infected with the polycythemia strain of Friend leukemia virus. The deduced amino acid sequence of a cDNA corresponding to a transcript originating from genomic DNA adjacent to Fli-2 is identical to that of the human heterogeneous nuclear ribonucleoprotein A1 gene, a member of the gene family of RNA-binding proteins involved in RNA splicing. In one erythroleukemia cell line, A1 expression was undetectable as a result of F-MuLV integration in one allele and loss of the other allele. These results suggest that perturbations in RNA splicing mechanisms may contribute to malignant transformation and provide direct evidence that the A1 protein is not required for cell growth.

scholarly journals Heterogeneous Nuclear Ribonucleoprotein A2B1 Exerts a Regulatory Role in Lipopolysaccharide-stimulated 38B9 B Cell Activation

2017 ◽  
Vol 17 (6) ◽  
pp. 437
Author(s):  
Jisang Park ◽  
Chung-Hyeon Choe ◽  
Ju Kim ◽  
Jing Shian Yang ◽  
Jin Hyun Kim ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Activation ◽  
Regulatory Role ◽  
B Cell Activation ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Nuclear Ribonucleoprotein
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