Evaluating the role of DNAJ chaperones on PolyQ aggregation in PolyQ expressing HEK293 cell lines using CRISPR-dCas9 knock-down
(2020) MOBN02 20201Degree Projects in Molecular Biology
- Popular Abstract
- Guardian proteins help or hinder clumpy proteins?
Proteins are products encoded by DNA in cells. They need to be folded in a certain structure to perform their function in the cell. Because of this, the proteins need a quality control system to ensure that they are folded correctly. A large group of proteins called as chaperones are important in this regard. The main role of chaperones is to fold the proteins to obtain a final functional structure and in addition, to correct misfolded proteins. The DNAJ co-chaperones assist the Hsp70s chaperones, by binding with the misfolded proteins and presenting them to Hsp70s, which lead to refolding of the misfolded proteins, converting them back to their functional structure.
Neurodegenerative... (More) - Guardian proteins help or hinder clumpy proteins?
Proteins are products encoded by DNA in cells. They need to be folded in a certain structure to perform their function in the cell. Because of this, the proteins need a quality control system to ensure that they are folded correctly. A large group of proteins called as chaperones are important in this regard. The main role of chaperones is to fold the proteins to obtain a final functional structure and in addition, to correct misfolded proteins. The DNAJ co-chaperones assist the Hsp70s chaperones, by binding with the misfolded proteins and presenting them to Hsp70s, which lead to refolding of the misfolded proteins, converting them back to their functional structure.
Neurodegenerative diseases are characterized by the loss of neurons with aging and they are becoming an increasing problem as the world population in general have an increased life span. Alzheimer´s, Parkinson´s and Huntington´s diseases are such diseases and are all characterized by accumulation of certain aggregated proteins in the brain. Huntington´s disease is caused by changes in the Huntingtin gene leading to increased aggregation of Huntingtin protein. The purpose of this study was to analyze if DNAJ genes are important suppressors of aggregation caused by the changes in Huntingtin gene. The Huntingtin protein clumps hinder the communication between neurons which results in mood and mental disorders followed by lack of motor co-ordination causing jerky body movements. This disease can be genetically inherited from parents who have mutations in Huntingtin coding DNA.
Some DNAJs and Hsps are triggered when proteins aggregate into clumps in the brain, as their role is to either disintegrate the clumps or correct the protein folding to make it functional again. In simpler terms, consider having a broken bike which is taken to a repair shop and is fixed to make it useful again. Here, DNAJs are considered as an individual who takes the broken bike (misfolded proteins) to the repair shop (Hsp70). The misfolded proteins are repaired and rendered as functional proteins. In case, if the bike is severely damaged and cannot be reused, it will be destroyed at the shop. Similarly, if the protein aggregation is severe, it will be destroyed by the destruction proteins. Primarily, the role of an individual is to prevent the bike from damages or in case of any failures, it has to be taken to the shop. The same happens here with the DNAJs, where, some can prevent protein aggregation by themselves and some DNAJs disintegrate the already formed aggregates with the help of Hsp70s. There is also a converse theory that says DNAJs might help proteins to aggregate by changing the environment accordingly.
The aim of this study was to understand the individual roles of 10 DNAJ proteins on aggregation in Huntington´s disease. To decipher the functions of genes and proteins, one can either silence, activate or decrease the expression of a gene which subsequently alters the protein formation. This will in turn result in functional changes in the cell. In this study, the expression of 10 DNAJs were decreased to identify their effects of modulation on aggregation using cells that display Huntington´s disease. The preliminary test using 3 DNAJs whose expression have been decreased resulted in increase of aggregates. This means that, in natural conditions, when they have not been decreased, they protect the cells by reducing aggregation. Using this model which decreases the expression of DNAJs, one can find the individual functions of each DNAJ. This knowledge might help in designing new drugs that can target DNAJs to cure brain diseases occurring due to protein aggregation.
Master’s Degree Project in Molecular Biology 45 credits 2020
Department of Biology, Lund University
Advisor: Christian Hansen
Advisor´s Unit/Department: Molecular neurobiology lab, BMC, Faculty of Medicine, Lund University (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9028693
- author
- Muralitharan, Uthira
- supervisor
- organization
- course
- MOBN02 20201
- year
- 2020
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9028693
- date added to LUP
- 2020-09-09 11:48:56
- date last changed
- 2020-09-09 11:48:56
@misc{9028693,
author = {{Muralitharan, Uthira}},
language = {{eng}},
note = {{Student Paper}},
title = {{Evaluating the role of DNAJ chaperones on PolyQ aggregation in PolyQ expressing HEK293 cell lines using CRISPR-dCas9 knock-down}},
year = {{2020}},
}