Event Title

Genetic Screen for Nitrogen Fixation Deficient Mutants in the Cyanobacterium Anabaen

Graduation Year

2016

Location

Center for Natural Sciences, Illinois Wesleyan University

Start Date

18-4-2015 2:00 PM

End Date

18-4-2015 3:00 PM

Description

A fundamental question in biology is how a cell is able to differentiate and take on a specialized function. In an environment lacking bioactive nitrogen, Anabaena, a multicellular cyanobacterium, differentiates specialized cells that can assimilate atmospheric nitrogen into organic compounds. However, the genetic network that controls differentiation is incompletely understood. To determine the genes required for heterocyst differentiation, a piece of DNA capable of random insertion into the genome, called a transposon, was introduced into wild type Anabaena. These cells were then cultured on antibiotic-containing media to select for the cells in which the transposon had inserted into the genome. The resulting colonies were transferred to media lacking a source of bioactive nitrogen, and assessed for the ability survive. Whereas continued growth and green coloration on nitrogen-limited media suggested normal heterocyst development, colonies that became yellow suggested that at least on one gene responsible for heterocyst differentiation had been disrupted by the transposon. Yellowed colonies were rescued by placing them back on media containing bioactive nitrogen and the location of the transposon insertion was determined. The genes identified in this screen will be important to future work on the genetic network governing heterocyst development.

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Apr 18th, 2:00 PM Apr 18th, 3:00 PM

Genetic Screen for Nitrogen Fixation Deficient Mutants in the Cyanobacterium Anabaen

Center for Natural Sciences, Illinois Wesleyan University

A fundamental question in biology is how a cell is able to differentiate and take on a specialized function. In an environment lacking bioactive nitrogen, Anabaena, a multicellular cyanobacterium, differentiates specialized cells that can assimilate atmospheric nitrogen into organic compounds. However, the genetic network that controls differentiation is incompletely understood. To determine the genes required for heterocyst differentiation, a piece of DNA capable of random insertion into the genome, called a transposon, was introduced into wild type Anabaena. These cells were then cultured on antibiotic-containing media to select for the cells in which the transposon had inserted into the genome. The resulting colonies were transferred to media lacking a source of bioactive nitrogen, and assessed for the ability survive. Whereas continued growth and green coloration on nitrogen-limited media suggested normal heterocyst development, colonies that became yellow suggested that at least on one gene responsible for heterocyst differentiation had been disrupted by the transposon. Yellowed colonies were rescued by placing them back on media containing bioactive nitrogen and the location of the transposon insertion was determined. The genes identified in this screen will be important to future work on the genetic network governing heterocyst development.