Highly purified poly(A) polymerase (polynucleotide adenylyltransferase, EC 2.7.7.19), which synthesizes poly(A) from ATP substrate, can also catalyze hydrolysis of poly(A). The enzyme, designated as poly(A) hydrolase, requires either Mn2+ or Mg2+ for activity. Although AMP is the predominant product of the reaction, ADP and ATP are also formed. The enzyme is a 3'-exonuclease that does not degra...

Here we demonstrate a new regulatory mechanism for tRNA processing in Escherichia coli whereby RNase T and RNase PH, the two primary 3' → 5' exonucleases involved in the final step of 3'-end maturation, compete with poly(A) polymerase I (PAP I) for tRNA precursors in wild-type cells. In the absence of both RNase T and RNase PH, there is a >30-fold increase of PAP I-dependent poly(A) tails that ...

The B6.C-H2bm12 (bm 12) strain has a mutation in the I-A subregion of the murine H-2 complex and is characterized by a loss of serologically detected Ia antigens and a strong graft rejection and mixed lymphocyte response between parent and mutant. It was presumed that the mutation affected the Ia-1 gene and to determine the relationship of Ia antigens and Ir genes, the immune responses of mutan...

The DExD/H box RNA helicases retinoic acid-inducible gene-I (RIG-I) and melanoma differentiation associated gene-5 (mda-5) sense viral RNA in the cytoplasm of infected cells and activate signal transduction pathways that trigger the production of type I interferons (IFNs). Laboratory of genetics and physiology 2 (LGP2) is thought to influence IFN production by regulating the activity of RIG-I a...

European sea bass is highly susceptible to the betanodavirus RGNNV genotype, although the SJNNV genotype has also been detected in this fish species. The coexistence of both genotypes may affect the replication of both viruses by viral interaction or by stimulation of the host antiviral defense system in which the IFN I system plays a key role. IFN I triggers the transcription of interferon-sti...

Poly(ADP-ribose), identified in 1966 independently by three groups Strassbourg, Kyoto and Tokyo, is synthesized by poly(ADP-ribose) polymerases (PARP) from NAD(+) as a substrate in the presence of Mg(2+). The structure was unique in that it has ribose-ribose linkage. In the early-1970s, however, its function in vivo/in vitro was still controversial and the antibody against it was desired to hel...