Deoxyribonuclease genetics

Drosophila exhibit hypersensitivity to DNA cross-linking agents and are defective in a deoxyribonuclease. Genetics, 125, 813-819. 

A second tool employed by the genetic engineer is the enzyme terminal transferase that adds deoxyribonuclease residues to the 3 end of DNA strands creating 3 tails of a single type of residue. 

Lacks, S.A. (1970). Mutants of Diplococcus pneumoniae that lack deoxyribonucleases and other activities possibly pertinent to genetic transformation. J. Bacteriol. 101, 119-131. 

Although there is still no cure for cystic fibrosis, several pharmacologic techniques have been recently developed that may help decrease the viscosity of respiratory secretions in patients with this disease. One technique uses aerosol preparations that contain enzymes known as deoxyribonucleases. These enzymes can be inhaled to break down the large quantities of DNA that are present in respiratory secretions of patients with cystic fibrosis.48,104 Respiratory secretions in these patients often contain large amounts of DNA because the genetic material contained in airway in-... 

Dornase alfa is phosphorylated glycosylated recombinant human deoxyribonuclease. It is given daily by inhalation of a nebulised solution containing 2500 units (2.5 mg). It is of modest value only in patients with cystic fibrosis, whose genetic defect in chloride transport causes particularly viscous sputum. The blocked airways, as well as the sputum itself, are a trap for pathogens and the lysis of invading neutrophils leads to substantial levels of free and very viscous DNA within the CF airways. 

ATP-dependent deoxyribonucleases (DNase) are enzymes that hydrolyze the phosphodiester linkage between deoxyribonucleosides in the presence of ATP. These enzymes are thought to be involved in the processes of genetic recombination and repair of radiation damages. The ATP-dependent DNase from Micrococcus luteus (Mw 160 kDa) shows the activity for single or double stranded linear DNA via an end-attachment 3 5 exonucleolytic processive... 

Avery and his colleagues concluded that the DNA extracted from the virulent strain carried the inheritable genetic message for virulence. Not everyone accepted these conclusions, because protein impurities present in the DNA could have been the carrier of the genetic information. This possibility was soon elimtnated by the finding that treatment of the DNA with proteolytic enzymes did not destroy the transforming activity, but treatment with deoxyribonucleases (DNA-hydrolyzing enzymes) did. 

Whether the interaction between histone and DNA is specific and occurs in vivo to repress DNA is not certain. However, it cannot be excluded that the histones interfere with the polymerase reaction simply by making the primer unavailable in a fashion common to all basic polymers. Histones and protamines interfere with the hydrolysis of DNA by deoxyribonuclease, and it thus can be established that the interference results from the precipitation of substrate. Injected, histones have been claimed to interfere with DNA biosynthesis in regenerating liver. Such intriguing observations undoubtedly have to be confirmed in several laboratories before their full impact can be appreciated. In conclusion, modern studies suggest that histones may be important in the transfer of genetic information from DNA to messenger RNA, but the molecular details remain to be elucidated. 

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