Disease relevance of U1SNRNPBP

• Two cell lines (NH and HM1), established from patients with metastatic melanomas, were evaluated for the presence of activated cellular protooncogenes [1].

High impact information on U1SNRNPBP

• A 314-bp DNA element called Heartbreaker-hm1 (Hbr-hm1) was previously identified in the 3' untranslated region of a mutant allele of the maize disease resistance gene HM1 [2].
• This, coupled with the insertion of an Hbr element into an allele of the HM1 gene, suggested that this family might have spread recently throughout the genome [2].
• CHO cells stably transfected with cDNA encoding the human M1 muscarinic acetylcholine (HM1) receptor were treated with the cholinergic agonist carbachol at various concentrations for differing times [3].
• Treatment of CHO cells stably expressing the human M1 muscarinic acetylcholine (HM1) receptor with the cholinergic agonist carbachol results in a reduction in cellular levels of Gq alpha/G11 alpha [4].
• Parallel assessment of agonist-induced down-regulation of the HM1 receptor demonstrated that it was lost in concert with the G-protein [3].

Biological context of U1SNRNPBP

• Two family members (clones 46 and 11) show complete mRNA features [including ribosome binding sites (RBS), polyadenylation signals, and poly(A) tails], and encode the same protein (designated HM-1), but differ substantially in their 5' untranslated regions [5].
• In contrast, contact with virulent amoebae (HM1) caused loss of PMN motility, PMN degranulation, death, and occasional phagocytosis by the amoebae, which survived concentrations of greater than 1,000 PMNs/amoeba [6].
• Entamoeba histolytica HM1 supported the activation of human alternative and classical complement pathways in the absence of ameba-reactive antibodies [7].
• Northern blot analysis demonstrated increased expression of the c-myc gene (from 9 to 14 times) in NH and HM1 cell lines by densitometric comparison with human melanocyte cell lines [1].
• Experiments comparing two E. histolytica strains showed that normal cell proliferation under anaerobiosis was higher in strain HK9 than in HM1, which is highly virulent, but that metronidazol and clomipramine were less effective against HM1 [8].

Anatomical context of U1SNRNPBP

• These results strongly suggest that histidine-35 has an important role in the cytocidal action of HM-1 that participates in the binding process to the HM-1 receptor protein on the cell membrane, but it is not essential for the interaction with, and inhibition of, 1,3-beta-glucan synthase [9].
• We have explored the interaction of virulent and avirulent E. histolytica (HM1 and 303 respectively) with human polymorphonuclear leukocytes (PMNs) and Chinese hamster ovary (CHO) cells [10].

Associations of U1SNRNPBP with chemical compounds

• Full-length HM-1 is 246 amino acids long, has a predicted MW of 29431, is rich in arginine residues, has a pI of 10.25, and a mean hydrophobicity index of -1.23 [5].
• HM-1 contains no obvious hydrophobic N-terminal cleavable signal sequence, and no potential N-glycosylation sites, but does contain three highly conserved motifs present in U1-70K splicing factors, and contains numerous C-terminal Arg/Asp and Arg/Glu dipeptides characteristic of "RD" family members that function as regulators of mRNA splicing [5].
• Similar concentrations of carbachol (5 microM) were required to produce half-maximal stimulation of inositol phosphate generation and loss of each of the HM1 receptor and Gq alpha, and half-maximal losses of both receptor and Gq alpha were produced by 3 h of treatment with 1 mM-carbachol [3].
• The HM-1 protein was isolated in association with the peptidoglycan by extraction of whole cells or cell envelopes with 2% sodium dodecyl sulfate at 55 degrees C. Heating the peptidoglycan-HM-1 protein complex in the detergent at 100 degrees C resulted in the quantitative release of the protein [11].
• The cytotoxin was partially purified from the cell-free supernatant of sonicated E. histolytica HM1 trophozoites by ammonium sulfate precipitation and gel filtration [12].

Analytical, diagnostic and therapeutic context of U1SNRNPBP

• Analysis of c-myc expression by in situ hybridization in HM1 cells showed that expression was not localized to a sub-population of cycling cells and all cells were overexpressing c-myc mRNA [1].
• Isoelectric focusing experiments and amino acid analysis revealed that the HM-1 protein had a basic character and was moderately hydrophilic [11].
• Co-immunoprecipitation experiments showed that wild-type and H35A HM-1 directly interact with the 1,3-beta-glucan synthase complex [9].
• Diethylpyrocarbonate modification and site-directed mutagenesis studies of histidine-35 in HM-1 killer toxin (HM-1) have shown that a specific feature, the imidazole side chain of histidine-35, is essential for the expression of the killing activity [9].
• DNA and total RNA were extracted from clinical isolates of Entamoeba sp. and from sensitive strain of E. histolytica (HM1: IMSS) and subjected to polymerase chain reaction (PCR) and multiplex reverse transcription (RT)-PCR techniques [13].

References