Determining Patterns of Altered Gene Expression by Plant Mitochondria during Heat Stress

Event Center BC

Unlike the normal flow of information from the nucleus to other parts of the cell, organelles can send signals back to the nucleus, termed retrograde regulation. Mitochondrial retrograde regulation (MRR) is seen to regulate nuclear gene expression. Abiotic stresses, such as heat, affect nuclear gene expression through multiple MRR pathways. When a plant is under heat stress or other abiotic stresses there are large changes found in the expression of heat shock proteins (HSPs), specifically small heat shock proteins (sHSPs). sHSPs interact with proteins to help stabilize and prevent other proteins from denaturing in an attempt to save the cell. Arabadopsis thaliana has been used as a model to study the effects -on sHSPs from a molecular genetic approach. Our hypothesis was that mitochondrial retrograde regulation leads to an increase in gene expression, increasing the amount of heat shock proteins in the cell. In our project we isolated RNA samples from a transgenic line of Arabadopsis thaliana (AtHSP17.4) which had a sHSP being constitutively expressed. Following isolation, we performed RNA gel analysis and blotting. This allowed us to identify if there was altered gene expression due to signaling from the mitochondria. Our results indicated more AtHSP17.4 transcript RNA in the transgenic line; this suggests an effect on nuclear gene expression from the mitochondria due to MRR.