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A Screen For Neurospora Knockout Mutants Displaying Growth Rate Dependent Branch Density, Michael Watters, Michael Boersma, Melodie Johnson, Ciara Reyes, Evan Westrick, Erik Lindamood
A Screen For Neurospora Knockout Mutants Displaying Growth Rate Dependent Branch Density, Michael Watters, Michael Boersma, Melodie Johnson, Ciara Reyes, Evan Westrick, Erik Lindamood
Michael Watters
Branch density (the spatial distribution of branch initiation points along a growing hypha) in wild-type Neurospora has been shown to remain constant at different growth rates due to a hypothesized system which compensates for hyphal growth rate. Here we report the results of a survey of the Neurospora knockout library for mutants affecting this proposed growth rate compensation system. The mutants identified fail to maintain branching homeostasis at different growth rates, thus showing growth rate-dependent branch density. The gene functions highlighted by this screen are diverse with several emerging themes including: ubiquitin-binding proteins, kinases, metal binding/metal metabolism proteins, reactive oxygen …
A Homeostatic Set Point For Branching In Neurospora Crassa, Michael Watters, Christine Humphries, Ingrid De Vries, Anthony Griffiths
A Homeostatic Set Point For Branching In Neurospora Crassa, Michael Watters, Christine Humphries, Ingrid De Vries, Anthony Griffiths
Michael Watters
The mechanisms responsible for controlling hyphal extension and branching are still poorly understood. We have investigated these processes by studying their dependence on temperature and nutrient concentration. Tip growth is highly responsive to temperature change, increasing linearly from 4 to 37 °C. Over this range of temperatures the branching pattern shows virtually no response. Likewise, varying nutrient concentration does not affect branch distribution. Colonies subjected to rapid extreme temperature downshifts (for example from 25 to 4°) display a strong and highly predictable branching response. There are three stages to this response. First there is an initial lag phase of growth …
Action Of Repeat-Induced Point Mutation On Both Strands Of A Duplex And On Tandem Duplications Of Various Sizes In Neurospora, Michael Watters, Thomas Randall, Brian Margolin, Eric Selker, David Stadler
Action Of Repeat-Induced Point Mutation On Both Strands Of A Duplex And On Tandem Duplications Of Various Sizes In Neurospora, Michael Watters, Thomas Randall, Brian Margolin, Eric Selker, David Stadler
Michael Watters
In Neurospora crassa, DNA sequence duplications are detected and altered efficiently during the sexual cycle by a process known as RIP (repeat-induced point mutation). Affected sequences are subjected to multiple GC-to-AT mutations. To explore the pattern in which base changes are laid down by RIP we examined two sets of strains. First, we examined the products of a presumptive spontaneous RIP event at the mtr locus. Results of sequencing suggested that a single RIP event produces two distinct patterns of change, descended from the two strands of an affected DNA duplex. Equivalent results were obtained using an exceptional tetrad from …
Spontaneous Mutation During The Sexual Cycle Of Neurospora Crassa, Michael Watters, David Stadler
Spontaneous Mutation During The Sexual Cycle Of Neurospora Crassa, Michael Watters, David Stadler
Michael Watters
The DNA sequences of 42 spontaneous mutations of the mtr gene in Neurospora crassa have been determined. The mutantws ere selected among sexual spores to represent mutations arising in the sexual cycle. Three sexualcycle-specific mutational classes are described: hotspot mutants, spontaneous repeatinduced point mutation (RIPS) and mutations occurring during a mutagenic phase of the sexual cycle. Together, these three sexual-cycle-specific mutational classes account fo5r0 % of the mutations in the sexual-cycle mutational spectrum. One thiordf all mutations occurred at onoef two mutational hotspots that predominantly produced tandem duplications of varying lengths with short repeats at their endpoints. Neither of the …