Deoxyribonuclease I (EC 3.1.21.1 ), in the form of a bovine pancreatic enzyme preparation, occupies an important
place in the history of protein chemistry and enzymology: it was the first enzyme to be recognized as specific for DNA;
it was the first DNase to be crystallized; and it was the first DNase for which a specific protein inhibitor was
characterized.////////////Isolation and Characterization of Mouse Antral Oocytes Based on Nucleolar Chromatin Organization. Monti M et al. (2016) This protocol describes a simple and quick method to isolate and characterize mouse antral GV (Germinal Vesicle) oocytes as able (SN, Surrounded Nucleolus) or unable (NSN, Not Surrounded Nucleolus) to develop to the blastocyst stage after in vitro maturation (IVM) and in vitro fertilization (IVF). It makes use of Hoeschst33342 (or any other DNA intercalating dye) able to bind to the heterochromatin of the nucleolus showing a ring in the SN oocytes or not, like in the NSN oocytes. This represents the easiest and quickest way to sort both antral oocytes that can be eventually used for IVM or IVF procedures. Briefly, the protocol consists of the following steps: hormone injection to stimulate follicular growth; isolation of the oocytes at the GV stage from the antral compartment by puncturing the ovary with a sterile needle; preparation of thin glass pipettes for mouth pipetting of the oocytes; sorting of the oocytes with Hoechst33342 prepared at a supravital concentration; IVM, IVF or any other molecular/cellular analysis. Unfortunately there are still few evidences to sort SN and NSN oocytes using less invasive techniques. If and once they will be identified, they could be potentially applied to human assisted reproductive technologies, although with several aspects that should be modified. To date, this technique has potential implications to dramatically increase IVM and IVF successful procedures in both endangered and species with economic interest.////////////////// Nontoxic DNA dye
https://www.applichem.com/en/literature/more-information/dna-dye-nontox/
NCBI Summary:
This gene encodes a member of the DNase family. This protein is stored in the zymogen granules of the nuclear envelope and functions by cleaving DNA in an endonucleolytic manner. At least six autosomal codominant alleles have been characterized, DNASE1*1 through DNASE1*6, and the sequence of DNASE1*2 represented in this record. Mutations in this gene have been associated with systemic lupus erythematosus (SLE), an autoimmune disease. A recombinant form of this protein is used to treat the one of the symptoms of cystic fibrosis by hydrolyzing the extracellular DNA in sputum and reducing its viscosity. Alternate transcriptional splice variants of this gene have been observed but have not been thoroughly characterized. [provided by RefSeq, Jul 2008]
General function
Oncogenesis
Comment
Cellular localization
Nuclear
Comment
Ovarian function
Oogenesis
Comment
Stepinska U, Olszanska B (ZYGOTE. 9:1-7 2001) reported the detection of deoxyribonuclease I and II activities in Japanese
quail oocytes.
To establish a factor responsible for spermatozoal degeneration, the presence
of DNase activity was studied in vitro in extracts of Japanese quail oocytes
using lambda DNA/HindIII as a substrate. The experimental conditions were
designed to reveal the presence of either DNase I or DNase II activities,
separately. Degradation of the substrate DNA was evaluated by electrophoresis
on agarose gels stained with ethidium bromide. high activities of DNase I and
DNase II were found in the germinal discs of the largest vitellogenic oocytes.
DNase I activity was estimated to be about 3 x 10(-3) Kunitz units and DNase
II about 4 x 10(-2) Kunitz units per germinal disc. DNase I activity in an
oocyte seems to increase during oogenesis since DNA degradation by the
extracts from the germinal discs of the largest vitellogenic oocytes was much
higher than by those from previtellogenic and small vitellogenic oocytes. The
presence of high DNase I and II activities in the largest vitellogenic oocytes
would point to their role in degradation of DNA from supernumerary spermatozoa
entering the ovum during polyspermic fertilisation in birds. The enzymes could
be a factor, or one of the factors, in the late block to polyspermy in the
cytoplasm of avian eggs.
Expression regulated by
Comment
Ovarian localization
Oocyte
Comment
DNase I activity in pig MII oocytes: implications in transgenesis. Zannoni A et al. Several reliable methods to produce transgenic animals utilize the male genome. After penetration into oocyte, sperm DNA undergoes dramatic conformational changes that could represent a great opportunity for exogenous DNA to be integrated in the zygote genome. Among the enzymes responsible for sperm remodeling, a nuclease could be involved. The presence of a DNase I in oocytes has not been much investigated. To date, an immunolocalization of DNase I has been reported only in rat immature oocytes and the presence of nuclease activities has been shown in avian oocytes.The present study was conducted to verify whether a DNase-I like activity is present in MII mature pig oocytes. To do this, oocyte extracts were assessed for nuclease activity by a plasmid degradation assay and by zymography; these analyses evidenced a 33 kDa, Ca(2+)/Mg(2+) dependent DNase I-like activity that was inhibited by Zn(2+). A further identification of DNase I was achieved by Western blot, immunofluorescence and RT-PCR experiments. Moreover, the presence of the enzyme activity was confirmed by the rapid degradation of exogenous DNA microinjected into the ooplasm. Finally, the exogenous DNA transferred to oocyte by spermatozoa during sperm mediated gene transfer in vitro fertilisation protocol seemed to be protected from DNase I degradation and to persist in the ooplasm till 6 h.These results, together with the high efficiency of sperm based transgenesis methods, suggest that the association with spermatozoa protects exogenous DNA from nuclease activities.
Expression pattern of the Deoxyribonuclease 1 gene: lessons from the Dnase1 knockout mouse.
Napirei M,et al .
The tissue distribution of Deoxyribonuclease 1 (DNASE1, DNase I), a Ca 2+ and Mg 2+/Mn 2+-dependent secretory endonuclease, has previously been investigated. However, most of these studies did not account for the existence of different members of the DNASE1 gene family, did not differentiate between endogenous DNASE1 protein synthesis and its extracellular occurrence or were not performed with methods allowing both, a sensitive and a specific detection. Now we re-examined the DNASE1 gene expression pattern by taking advantage of the Dnase1 knockout mouse model. Direct comparison of samples derived from wildtype (Dnase1+/+) and knockout (Dnase1-/-) mice allowed an unambiguous detection of Dnase1 gene expression at the mRNA and protein level. For the detection of Dnase1 activity we developed a highly sensitive nuclease zymogram method. We observed high Dnase1 gene expression in the parotid and submandibular gland as well as in the kidney and duodenum, intermediate expression in the ileum, mesenterial lymph nodes, liver, ventral prostate, epididymis, ovary and stomach, and low expression in the sublingual, preputial, coagulation and pituitary gland. We report for the first time the lacrimal and thyroid gland, the urinary bladder and the eye to be Dnase1 expressing organs as well. Since Dnase1 knockout mice with the 129xC57Bl/6 mixed genetic background have indicated the protection against an anti-DNA autoimmune response as a new physiological function of Dnase1, knowledge of the physiological sites of its synthesis might prove helpful to find new therapeutic strategies.