Characterization of a putative plastid transporter PAAC

Transporters of the mitochondrial carrier family (MCF) are critical for cellular function because they transfer a variety of essential molecules across membrane-bound organelles such as mitochondria and chloroplast. However, little is known about MCF transporters in plastids, which contain the energy-generating, photosynthetic machinery in plants.  Characterization of plastid-localized MCF proteins will further understanding of plastid development and function, and is therefore essential for advancements in agriculture, biofuels, and medicine. During my internship, I worked with two Arabidopsis PAAC genes, At3G5187 (AtPAAC1) and At5G01500 (AtPAAC2). I first confirmed genotypes of the progeny of heterozygous AtPAAC1 and then examined RNA transcript levels in Atpaac1 andAtpaac2 mutants compared to wild type plants. T-DNA insertion lines showed reduced transcript level in paac1 mutant and no transcript in paac2 mutant, which confirmed that the T-DNA insertions interfere with gene expression. Next, double heterozygotes were generated to create a paac1; paac2double mutant and the phenotype will be examined. The maize genome has one PAAC gene (GRM2M2G178460) whose expression level is high in developing photosynthetic tissue such as young leaves. We selected a fragment that is approximately 100 amino acids long from the c-terminal of the protein and expressed it in E. coli. An antibody raised against this antigen will be used to detect and localize the maize PAAC protein. I also helped prepare maize leaf samples from mutant and wild type plants for transmission electron microscopy. These images will illuminate any structural changes in mutant plastid.

My Experience

Through this internship, I have explored the world of graduate student life. I have learned how to approach a scientific project, how to work with mentors, PI’s, and lab mates, and what to expect during graduate school. Events with graduate students were especially helpful in shaping a complete understanding of grad life in Ithaca. In the lab I have gained valuable understanding of plant biochemical procedures as well as presentation and scientific writing skills. Weekly seminars were a helpful way to get to know all of the different faculty and research topics at both BTI and Cornell. I really enjoyed the experience of living in Ithaca and being a part of the academic community there. I am coming away from this internship with a broader understanding of the academic world and what part I can play in it. Thank you BTI and the Van Wijk lab for this opportunity!