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Biomedical subjects

M Munn

Publications and source records attributed to M Munn.

8 recordsLinked to original sources
PubMed1999

The involvement of genome researchers in high school science education.

The rapid accumulation of genetic information generated by the Human Genome Project and related research has heightened public awareness of genetics issues. Education in genome science is needed at all levels in our society by specific audiences and the general public so that individuals can make well-informed decisions related to public policy and issues such as genetic testing. Many scientists have found that an effective vehicle for reaching a broad sector of society is through high school biology courses. From an educational perspective, genome science offers many ways to meet emerging science learning goals, which are influencing science teaching nationally. To effectively meet the goals of the science and education communities, genome education needs to include several major components-accurate and current information about genomics, hands-on experience with DNA techniques, education in ethical decision-making, and career counseling and preparation. To be most successful, we have found that genome education programs require the collaborative efforts of science teachers, genome researchers, ethicists, genetic counselors, and business partners. This report is intended as a guide for genome researchers with an interest in participating in pre-college education, providing rationale for their involvement and recommendations for ways they can contribute, and highlighting a few exemplary programs. World Wide Web addresses for all of the programs discussed in this report are given in Table 1. We are developing a database of outreach programs offering genetics education () and request that readers submit an entry describing their programs. We invite researchers to contact us for more information about activities in their local area.

Adolescent↗
PubMed1991

Requirement for the replication protein SSB in human DNA excision repair.

Replication and repair are essential processes that maintain the continuity of the genetic material. Dissection of simian virus 40 (SV40) DNA replication has resulted in the identification of many eukaryotic replication proteins, but the biochemistry of the multienzyme process of DNA excision repair is less well defined. One protein that is absolutely required for semiconservative replication of SV40 DNA in vitro is human single-stranded DNA-binding protein (SSB, also called RF-A and RP-A). SSB consists of three polypeptides of relative molecular mass 70,000, 34,000 and 13,000, and acts with T antigen and topoisomerases to unwind DNA, allowing the access of other replication proteins. Human SSB can also stimulate the activity of polymerases alpha and delta, suggesting a further role in elongation during DNA replication. We have now found a role for human SSB in DNA excision repair using a cell-free system that can carry out nucleotide excision repair in vitro. Monoclonal antibodies against human SSB caused extensive inhibition of DNA repair in plasmid molecules damaged by ultraviolet light or acetylaminofluorene. Addition of purified SSB reversed this inhibition and further stimulated repair synthesis by increasing the number of repair events. These results show that a mammalian DNA replication protein is also essential for repair.

Antibodies, Monoclonal↗
PubMed1989

Localization of DNA repair synthesis by human cell extracts to a short region at the site of a lesion.

Double-stranded bacteriophage M13 DNA molecules were constructed containing a single specifically placed 2-(acetylamino)fluorene adduct or a single 4'-hydroxymethyl-4,5',8-trimethylpsoralen monoadduct. These circular DNA molecules were used to analyze in vitro DNA repair synthesis by cell extracts from normal human lymphoid cell lines. Both types of lesions stimulate DNA repair synthesis at the site of the adduct. DNA repair synthesis induced by the 2-(acetyl-amino)fluorene adduct took place in the damaged strand and was confined to a region within a 31-base pair restriction fragment around the adduct.

2-Acetylaminofluorene↗
PubMed1989

Sequence-specific pausing during in vitro DNA replication on double-stranded DNA templates.

Sequence-specific pausing occurs during DNA synthesis catalyzed by the bacteriophage T4 DNA polymerase holoenzyme in the presence of the T4 helix destabilizing protein (gene 32 protein). Two of the six strongest pause sites on a double-stranded bacteriophage fd DNA template are in regions where hairpin helices are predicted to form when the DNA is single stranded. However, the other pause sites are in regions that are not obviously involved in secondary structure. The positions of the DNA chain ends produced at one pause site of each type were determined to within +/- 2 nucleotides. At this resolution, a clustering of sites is observed, suggesting that the polymerase holoenzyme may become destabilized when moving along selected regions of the DNA and then pause at one or more of several closely spaced positions. The addition of the T4 gene 41 protein (a DNA helicase that forms part of the T4 primosome) to the above replication system greatly increases the rate of fork movement and eliminates detectable pausing. In contrast, the addition of the T4 dda protein (a second DNA helicase that increases the rate of fork movement to a similar extent) has no affect on replication fork pausing. This difference could either be due to specific protein-protein interactions formed between the polymerase holoenzyme and the 41 protein or to the highly processive movement of the 41 protein along the displaced DNA strand.

Base Sequence↗
PubMed1985

Purification and properties of the bacteriophage T4 gene 61 RNA priming protein.

The bacteriophage T4 gene 61 protein is required, together with the gene 41 protein and single-stranded DNA, for the synthesis of the pentaribonucleotides that are used as primers for the start of each new Okazaki DNA fragment during T4 DNA replication. Using this priming activity as an assay, we have purified the 61 protein to essential homogeneity in milligram amounts. The priming activity was identified with the product of T4 gene 61 by using two-dimensional polyacrylamide gel electrophoresis to compare all of the T4-induced proteins in wild-type and mutant infections; the purified protein co-migrates with the only detectable protein missing in a 61- mutant infection. The purified 61 protein is shown to bind to the T4 helix-destabilizing protein (gene 32 protein) and to both single-stranded and double-stranded DNA. We have failed to detect any ribonucleotide polymerizing activity in either the 61 protein or the 41 protein alone; both the 61 and 41 proteins must be present to observe any synthesis of oligoribonucleotides.

Chromatography↗