Article Abstract:
RNA triphosphatase, guanylyl-transferase and methyltransferase are enzymatic activities wherein sequential action is needed by mRNA capping. The gene (CEL-1) is believed to encode the C.elegans capping enzymes and has a C-terminal domain having motifs detected in yeast and vaccinia virus capping enzyme guanylyltransferases. The N-terminal domain of CEL-1 has a noticeable sequence resemblance to the protein tyrosine phosphatase (PTP) enzyme family although it does not have detectable PTP activity. Furthermore, this domain is not similar to vaccinia virus capping enzyme even though it has RNA triphosphatase activity.
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Article Abstract:
A study was conducted to identify TXB181, which was characterized as the human homolog of yeast mitotic checkpoint MAD1 protein (HsMAD1), as the target of the human T cell leukemia virus type 1 (HTLV-1) oncoprotein Tax. HsMAD1 functions as a homodimer which localizes to the centrosome during metaphase and to the spindle midzone and the midbody during anaphase and telephase stages. It was observed that expression of either Tax or a transdominant-negative TXBP181 results in multinucleated cells, a phenotype consisttent with a loss of HsMAD1 function.
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Article Abstract:
The mechanistic consequences of protein-protein contacts that activate and repress prokaryotic transcription are discussed. The transcription initiation has been influenced by in vitro studies wherein RNA polymerase recognizes and binds to double-stranded promoter DNA to form a closed complex. RNA polymerase directly promotes the synthesis of short abortive products while escaping from the promoter by breaking contacts that stabilize the open complex.
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