Biomedical subjects

Robert J Donnelly

Publications and source records attributed to Robert J Donnelly.

4 recordsLinked to original sources

PubMed2005

Cloning and characterization of the 5' flanking region of the HGFIN gene indicate a cooperative role among p53 and cytokine-mediated transcription factors: relevance to cell cycle regulation.

HGFIN, previously identified as nmb, and its homologs, osteoactivin are single transmembrane protein that is expressed in differentiated immune cells, and are linked to tumor progression. These dichotomous roles suggest that HGFIN could be linked to cell cycle regulation. We hypothesize that HGFIN is linked to different phases of cell cycle regulation via specific transcription factors. This study cloned and analyzed two fragments in the 5' flanking region of HGFIN: HGFIN-RM/2.0: 2.0 kb upstream of Exon 1; HGFIN-RM/1.5: 5' deletion (500 bp) of HGFIN-RM/2.0. Computer analyses indicated that HGFIN has unique upstream sequence with eight potential p53 sites. Electrophoretic mobility shift assay with Cy3-labeled PCR fragments indicated that p53 could interact with fragments encompassing p53 consensus regions. Reporter gene activities with HGFIN-RM/2.0 and HGFIN-RM/1.5 in cells with different p53 levels showed that p53 is relevant to HGFIN activities. Studies with modified T47D in which cytokine production was downregulated, but with p53 level similar to parental line showed synergism between p53 and mediators of cytokine in the regulation of HGFIN. In summary, p53 cooperate with cytokine-mediated transcription factors to regulate the expression of HGFIN.

5' Flanking Region↗

PubMed2004

A functional interaction between RHA and Ubc9, an E2-like enzyme specific for Sumo-1.

RNA helicase A (RHA) is a member of the DEAH helicase family of proteins. Recent studies imply the role of RHA in the regulation of the topology of chromatin DNA, which could influence diverse nuclear processes such as transcription activity of the chromatin DNA and chromosome condensation. We previously reported that Ubc9, an E2-like enzyme specific for small ubiquitin-like modifier 1 (Sumo-1), is required for the interaction between RHA and topoisomerase IIalpha. Here, we describe that Ubc9 is a novel factor that functionally interacts with RHA and activates the transcription activity of RHA, measured in the CREB-mediated pathway. We demonstrate that the N-terminal domain of RHA, encompassing amino acid residues 1-137, is sufficient for its interaction with Ubc9. Our data also show that interaction with Ubc9 leads to the Sumo-1 conjugation of RHA both in vitro and in vivo. However, the catalytic activity of Ubc9 seems to be dispensable for the transcription activation activity of RHA. Our observation suggests multiple roles for Ubc9 in the regulation of the RHA function.

Amino Acid Sequence↗

PubMed2003

Functional analysis of the subunits of the chromatin assembly factor RSF.

The human ISWI-containing factor RSF (for remodeling and spacing factor) is composed of two subunits: the ATPase hSNF2H and p325 (Rsf-1), a protein encoded by a novel human gene. We previously showed that RSF mediates nucleosome deposition and generates regularly spaced nucleosome arrays. Here we report the characterization of the largest subunit of RSF, Rsf-1. We found that Rsf-1 is a highly acidic protein containing a plant homology domain. The present study includes the cloning of Rsf-1, the preparation of recombinant RSF, and the dissection of the role of each subunit in the chromatin assembly reaction. The sequence of the gene for Rsf-1 includes a recently characterized cDNA, HBXAP; postulated to be involved in the transcriptional regulation of the hepatitis B virus. HBXAP actually contains a 252-amino-acid truncation of the amino terminus of Rsf-1. Finally, comparison of HBXAP and Rsf-1 properties shows that they are functionally different.

Adenosine Triphosphatases↗

PubMed2002

Signaling of monocytic differentiation by a non-hypercalcemic analog of vitamin D3, 1,25(OH)2-5,6 trans-16-ene-vitamin D3, involves nuclear vitamin D receptor (nVDR) and non-nVDR-mediated pathways.

Exposure of leukemia cells to the physiologically active form of vitamin D3, 1,25-dihydroxyvitamin D3 (1,25D3) normalizes their phenotype to cells that resemble mature monocytes. One of the earliest detectable events in this process is an upregulation of the nuclear receptor for 1,25D3, the vitamin D receptor (nVDR). In contrast, the novel analog of 1,25D3, 1,25-dihydroxy-5,6 trans-16-ene-vitamin D3 (5,6-16D3), which has recently been reported to have low calcium-mobilizing activity in vivo, rapidly induced the expression of CD14, CD11b, and monocyte-specific esterase (MSE), classical markers of the mature monocyte, but upregulated nVDR expression less than 1,25D3. This upregulation was shown to be the result of altered degradation of the nVDR protein, while the levels of nVDR mRNA were constant. Knock-out of nVDR transcriptional activity by a decoy VDRE double-stranded deoxyoligonucleotide, markedly abrogated 1,25D3-induced differentiation, but incompletely inhibited 5,6-16D3-induced differentiation. These findings suggest that the unique ability of 5,6-16D3 to induce cell differentiation but not systemic hypercalcemia, may be due to the activation of pathways which initiate differentiation independently of nVDR.

Antineoplastic Agents↗