Exploring the Specialization of Expansion Segments in Stage-Specific Plasmodium Ribosomes
Open Access
- Author:
- Wardeh, Leena
- Area of Honors:
- Biology
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Scott E. Lindner, Thesis Supervisor
Timothy J Jegla, Thesis Honors Advisor - Keywords:
- malaria
parasites
parasitology
molecular biology
ribosomes
ribosomal specialization
expansion segments
Leena Wardeh
Scott Lindner
James McGee
Allen Minns
RNA
DNA
RNA probes
polyacrylamide gel
transcription
translation
electroelution
biotinylation
sequencing
EMSA - Abstract:
- Malaria, a deadly disease caused by the Plasmodium parasite, remains a significant threat to public health worldwide. Developing effective drugs to combat malaria is challenging due to the parasite's ability to rapidly develop resistance to antimalarials, as seen with existing medications such as chloroquine, quinine, sulfadoxine, and halofantrine. However, a potential target for novel antimalarials lies in the unique, heterogenous ribosomes found in Plasmodium, and their temporally expressed Asexual (A) and Sporozoite (S) types. These ribosomes contain sequence variations between their rRNAs, particularly in expansion segments (ESs), which are protrusions of ribosomal RNA (rRNA) sequences outside the conserved core rRNA. While the functional roles of eukaryotic ESs are not fully understood, they play crucial roles in ribosome biogenesis and recruit specific effector proteins acting on nascent polypeptides. This evidence of rRNA ES interactions with ribosome-associated factors in eukaryotes leads me to hypothesize that certain rRNAs varying between A- and S-type ribosomes may interact with a protein complex crucial for Plasmodium ribosome specialization. The aim of this project was to develop a reproducible protocol to generate ES probes identical in size and sequence to Plasmodium's ES9S and ES27L sequences that protrude from A-type and S-type ribosomes. I established the experimental workflow by exclusively focusing on creating control ES GFP RNA probes designed to mirror the approximate sequence length and predicted structure of the three sequences for both the P. yoelii ES9S sequence and ES27L sequence, located on Chromosomes 5, 6, and 12. These ESs were chosen for investigation because of their demonstrated specialized functions in other eukaryotic organisms. Throughout this project, I established a reliable and consistent protocol for generating these RNAs that can be applied to the remaining ES RNA probes chosen for this study. This will enable efforts to determine whether the other six ES9S and ES27L A-type and S-type ES possess the capacity to selectively bind effector proteins. These results would demonstrate their specialized translational function in Plasmodium, which could advance understanding of stage-specific Plasmodium ribosomes and their role in translational regulation throughout the malaria life cycle. Through the generation of ES RNA probes known to have specialized functions in other eukaryotic organisms, we aim to uncover whether similar specialized functions exist in Plasmodium, potentially offering valuable targets for vaccines or medications focused on disrupting the translational dynamics of malaria.