Functional analysis of Gna-2, a G protein alpha subunit from the filamentous fungus Neurospora Crassa /
Heterotrimeric G proteins, consisting of a, 0 and y subunits, mediate a variety of signaling pathways in all eukaryotic organisms. The filamentous fungus Neurospora crassa had been shown previously to have two G protein a subunits, Gna- 1 and Gna-2. Preliminary studies suggested that Gna-2 is esse...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739639991&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Heterotrimeric G proteins, consisting of a, 0 and y subunits, mediate a variety of signaling pathways in all eukaryotic organisms. The filamentous fungus Neurospora crassa had been shown previously to have two G protein a subunits, Gna- 1 and Gna-2. Preliminary studies suggested that Gna-2 is essential for the vegetative growth of N. crassa (Lu, 1994). The objectives of this work were to determine if Gna-2 is essential and to elucidate its functions. By the method of RIP & Rescue, it was determined that Gna-2 is dispensable for growth and viability. []gna-2 deletion mutants were then made by targetted gene replacement. Extensive phenotypic analysis of []gna-2 strains did not reveal any major abnormality during vegetative or sexual development. However, deletion of gna-2 in a []gna-1 strain accentuated the []gna-1 phenotypes. []gna-1 []gna-2 strains have a slower rate of hyphal apical extension on hyperosmotic media and more pronounced defects in female fertility than []gna-1 strains. One explanation for these results is that gna-1 and gna-2 have overlapping functions in N. crassa. Deletion of the gna-2 gene has helped identify a third G protein a subunit, Gna-3. A fragment of the gna-3 gene was amplified by Polymerase Chain Reaction using genomic DNA from a []gna-2 strain. Preliminary DNA sequencing indicated that gna-3 contains an intron at a conserved position within genes encoding the Gi family of higher eukaryotes. |
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| Item Description: | Vita. "Major Subject: Plant Pathology". In title, numerals and symbols are used. |
| Physical Description: | ix, 79 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 69-78. |