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You searched for +publisher:"Cornell University" +contributor:("Lazarowitz, Sondra Gale"). Showing records 1 – 2 of 2 total matches.

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Cornell University

1. Sun, Tao. Trans-Acting Factors Essential For Plant Organelle Rna Editing.

Degree: PhD, Plant Biology, 2014, Cornell University

In higher plants, RNA editing is a C-to-U conversion that corrects chloroplast and mitochondrial transcripts that are otherwise defective. Although plant RNA editing has been known for over two decades, the molecular mechanism is poorly understood. Until recently, all the known trans-acting factors were members of the Pentatricopeptide Repeat (PPR) protein family, which serve as recognition factors via specific interaction with cis-elements upstream of the C targets. An additional editing factor, RIP1, was identified by a proteomics study. RIP1 is a dual-targeted protein that selectively interacts with PPR editing factors and affects 14 editing events in chloroplasts and over 400 editing events in mitochondria. RIP1 belongs to a small protein family, 5 members of which were later shown to be major editing factors. Homology searching with the RIP protein led to the discovery of ORRM1, a hybrid protein which possesses a RIP-like domain at its N terminus and an RNA Recognition Motif (RRM) domain at its C terminus. Loss of ORRM1 results in editing defects in multiple plastid sites. A transient complementation assay indicates that the editing activity of ORRM1 is carried by the RRM, which places it in a different family than RIP proteins. Additional members of the ORRM1 family might be involved in plant RNA editing. A plastid-targeted protein immunoprecipitated with a functional epitopetagged ORRM1. Loss of this protein leads to editing defects at many plastid sites, most of which are also controlled by ORRM1. Homology searches with this plastid protein identified several related proteins which are all organelle-targeted. The function of this new family still needs further investigation. So far, four types of trans-acting factors have been identified for plant organelle RNA editing, which reveals an unexpected complexity of the editing machinery. Advisors/Committee Members: Hanson, Maureen R (chair), Van Wijk, Klaas (committee member), Lazarowitz, Sondra Gale (committee member).

Subjects/Keywords: plant RNA editing; chloroplast and mitochondria

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Sun, T. (2014). Trans-Acting Factors Essential For Plant Organelle Rna Editing. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/38935

Chicago Manual of Style (16th Edition):

Sun, Tao. “Trans-Acting Factors Essential For Plant Organelle Rna Editing.” 2014. Doctoral Dissertation, Cornell University. Accessed December 01, 2020. http://hdl.handle.net/1813/38935.

MLA Handbook (7th Edition):

Sun, Tao. “Trans-Acting Factors Essential For Plant Organelle Rna Editing.” 2014. Web. 01 Dec 2020.

Vancouver:

Sun T. Trans-Acting Factors Essential For Plant Organelle Rna Editing. [Internet] [Doctoral dissertation]. Cornell University; 2014. [cited 2020 Dec 01]. Available from: http://hdl.handle.net/1813/38935.

Council of Science Editors:

Sun T. Trans-Acting Factors Essential For Plant Organelle Rna Editing. [Doctoral Dissertation]. Cornell University; 2014. Available from: http://hdl.handle.net/1813/38935


Cornell University

2. Ray, Gregory. Arabidopsis Thaliana Syta As A Model To Address Whether Synaptotagmin Proteins Function As Dimers Or Tetramers.

Degree: PhD, Molecular and Cell Biology, 2014, Cornell University

The Arabidopsis thaliana synaptotagmin SYTA (AT2G20990) regulates endocytosis at the plasma membrane and virus movement protein-mediated cellto-cell movement. As with all synaptotagmin proteins, SYTA is predicted to consist of a transmembrane domain, a cytosolic variable domain, and two calcium/lipid binding domains (C2A and C2B) at its COOH-terminus. Deletion of the C2B domain abolishes SYTA function. The C2B deleted mutant of SYTA also acts as a dominant-negative mutant as evidenced by its interference with endogenous, wild-type SYTA. This finding is consistent with the unproven hypothesis that synaptotagmin proteins in animals potentially function as dimers or tetramers. However, the existence of a SYTA C2B domain in plants that is functionally similar to those in animal synaptotagmins has been questioned by some research groups. In this project, I utilized molecular modeling to predict how a homodimer of SYTA may function, and cell-based functional assays and in vitro biochemical approaches to demonstrate the relevance of the model I created. I modeled SYTA-C2B to explain how the C2B domains from the individual proteins within a dimer could function to bind calcium. I demonstrated that key residues from this model (E430, D431, and E433) were functionally relevant by expressing alanine point mutants of each in protoplasts and observing that they did not localize to endosomes effectively. My research was consistent with the prediction that E430 and D431 are essential for SYTA function, possibly forming the core of a calcium-binding site. Although it is not essential in this activity, I also concluded that E433 may improve the calciumsensing ability of C2B. By utilizing dynamic and static light scattering, I observed that purified SYTA is a dimer, which indicated calcium binding via the C2B domain is not required for the formation of this dimer. This research is the first direct observation of a synaptotagmin protein, plant or animal, forming a dimer. Advisors/Committee Members: Lazarowitz, Sondra Gale (chair), Vogt, Volker M (committee member), Parrish, Colin Ross (committee member).

Subjects/Keywords: Synaptotagmin; Endocytosis; SYTA

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Ray, G. (2014). Arabidopsis Thaliana Syta As A Model To Address Whether Synaptotagmin Proteins Function As Dimers Or Tetramers. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/37059

Chicago Manual of Style (16th Edition):

Ray, Gregory. “Arabidopsis Thaliana Syta As A Model To Address Whether Synaptotagmin Proteins Function As Dimers Or Tetramers.” 2014. Doctoral Dissertation, Cornell University. Accessed December 01, 2020. http://hdl.handle.net/1813/37059.

MLA Handbook (7th Edition):

Ray, Gregory. “Arabidopsis Thaliana Syta As A Model To Address Whether Synaptotagmin Proteins Function As Dimers Or Tetramers.” 2014. Web. 01 Dec 2020.

Vancouver:

Ray G. Arabidopsis Thaliana Syta As A Model To Address Whether Synaptotagmin Proteins Function As Dimers Or Tetramers. [Internet] [Doctoral dissertation]. Cornell University; 2014. [cited 2020 Dec 01]. Available from: http://hdl.handle.net/1813/37059.

Council of Science Editors:

Ray G. Arabidopsis Thaliana Syta As A Model To Address Whether Synaptotagmin Proteins Function As Dimers Or Tetramers. [Doctoral Dissertation]. Cornell University; 2014. Available from: http://hdl.handle.net/1813/37059

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