Bacteriophage T4 encodes a 5Ј-to 3Ј-nuclease with T4 RNase H activity which removes the pentamer RNA primers synthesized during lagging strand DNA replication (1). This T4-encoded nuclease is sufficient for phage DNA synthesis because wild type T4 does not require host enzymes for processing of RNA primers (2). Escherichia coli polymerase I and RNase HI can substitute to some extent if T4 RNase H is deleted, but replication is slower and less accurate in the absence of the T4 enzyme (2).The 5Ј-to 3Ј-nuclease of T4 RNase H degrades both RNA⅐DNA and DNA⅐DNA duplexes, releasing short oligonucleotide products from the 5Ј-end. In the accompanying paper (3) we have shown that T4 RNase H continues to degrade double-stranded DNA until it reaches 8 -11 nucleotides from the 3Ј-end. Although T4 RNase H by itself is a nonprocessive exonuclease, the rate and processivity of the nuclease reaction are increased by the T4 gene 32 single-stranded DNA-binding protein. At the T4 DNA replication fork, single-stranded DNA is covered with the gene 32 protein; hence, T4 RNase H must be acting as a processive exonuclease, removing the RNA primer and some adjacent DNA. Our recent results indicate that this nuclease performs only one round of processive degradation during each lagging strand cycle, removing 10 -50 nucleotides before polymerase elongates the next Okazaki fragment creating a nick sealed by ligase.
These results suggest that postoperative infusion of bupivacaine may be efficacious for enhancing pain relief after bone harvest in pediatric patients and may enhance parental perceptions of postoperative care; however, this patient population is difficult to study accurately.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.