Mping Transposition Requires Nucleotide Specific Interactions With The Terminal Inverted Repeats

Cayla Odom

School Name

Governor's School for Science and Math

Grade Level

12th Grade

Presentation Topic

Cell and Molecular Biology

Presentation Type

Mentored

Mentor

Mentor: Dr. Nathan Hancock; Department of Biology and Geology, University of South Carolina Aiken

Oral Presentation Award

1st Place

Abstract

Since their discovery in maize in the 1950’s, the roles and characteristics of transposable elements (TEs) have continued to be focal areas of research for their roles in genome evolution. Transposable elements are pieces of DNA that can move, or transpose, throughout a genome. Our experiment further analyzed transposition by investigating the base interactions in the rice TE Ping. Our focal region flanked the element in an area known as the terminal inverted repeats (TIRs). We hypothesized that highly conserved bases play a key role in transposition, testing the fifteen bases of the Ping TIRs. We PCR amplified the region using mutated primers to create fifteen constructs, each with a different mutated base. Two rounds of PCR were performed, one to make one base unreadable due to mutation and another to attach an additional sequence, which allowed for construct transformation into yeast. A yeast transposition assay was performed to identify successful transposition for each mutated base, as colonies only grow if the element transposes. Higher colony counts indicated greater rates of transposition. According the resulting transposition rates from the assay, all TIR bases were important for transposition. The conserved bases, save one at base position 5, had a lower transposition rate compared to the control construct. The element could not transpose when a conserved base was made unreadable through mutation. These results show that the transposition requires require specific nucleotides. It also suggests that certain transposable element bases remained conserved due to their role in transposition.

Location

Owens 201

Start Date

4-16-2016 11:00 AM

COinS
 
Apr 16th, 11:00 AM

Mping Transposition Requires Nucleotide Specific Interactions With The Terminal Inverted Repeats

Owens 201

Since their discovery in maize in the 1950’s, the roles and characteristics of transposable elements (TEs) have continued to be focal areas of research for their roles in genome evolution. Transposable elements are pieces of DNA that can move, or transpose, throughout a genome. Our experiment further analyzed transposition by investigating the base interactions in the rice TE Ping. Our focal region flanked the element in an area known as the terminal inverted repeats (TIRs). We hypothesized that highly conserved bases play a key role in transposition, testing the fifteen bases of the Ping TIRs. We PCR amplified the region using mutated primers to create fifteen constructs, each with a different mutated base. Two rounds of PCR were performed, one to make one base unreadable due to mutation and another to attach an additional sequence, which allowed for construct transformation into yeast. A yeast transposition assay was performed to identify successful transposition for each mutated base, as colonies only grow if the element transposes. Higher colony counts indicated greater rates of transposition. According the resulting transposition rates from the assay, all TIR bases were important for transposition. The conserved bases, save one at base position 5, had a lower transposition rate compared to the control construct. The element could not transpose when a conserved base was made unreadable through mutation. These results show that the transposition requires require specific nucleotides. It also suggests that certain transposable element bases remained conserved due to their role in transposition.