Northern Kentucky University

Strategies for identifying important residues in the tRNA modification protein Trm732

Grade Level at Time of Presentation

Junior

Major

Chemistry

Minor

Biological Sciences

2nd Grade Level at Time of Presentation

Sophomore

2nd Student Major

Chemistry

2nd Student Minor

Biological Sciences

KY House District #

63; 66

KY Senate District #

23; 11

Department

Dept. of Chemistry and Biochemistry

Abstract

Post-transcriptional tRNA modifications are required for efficient protein translation. In yeast, the Trm7 methyltransferase forms a complex with Trm732 to modify tRNA at position 32. In humans, lack of the human homolog for Trm7, FTSJ1, causes intellectual disability. Little is known about the function of Trm732, although we have shown that one conserved motif in Trm732 is important for tRNA modification. We have identified other residues important for function using two strategies. First, we compared Trm732 proteins of different organisms using protein alignments to determine conserved regions to mutate for testing. We have generated four new Trm732 variants and have tested their function. Second, we have worked at expressing randomly mutated Trm732 variants in a sick strain that lacks Trm732. Lack of rescue of the strain indicates that the mutation present is harmful to protein function. DNA from these colonies have been extracted and sequenced to determine the mutation that causes loss of Trm732 function. The human homolog for Trm732, THADA, has been linked to some forms of cancer and type II diabetes. The identification of Trm732 variants that cause loss of tRNA modification activity would help to determine how THADA is related to other diseases.

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Strategies for identifying important residues in the tRNA modification protein Trm732

Post-transcriptional tRNA modifications are required for efficient protein translation. In yeast, the Trm7 methyltransferase forms a complex with Trm732 to modify tRNA at position 32. In humans, lack of the human homolog for Trm7, FTSJ1, causes intellectual disability. Little is known about the function of Trm732, although we have shown that one conserved motif in Trm732 is important for tRNA modification. We have identified other residues important for function using two strategies. First, we compared Trm732 proteins of different organisms using protein alignments to determine conserved regions to mutate for testing. We have generated four new Trm732 variants and have tested their function. Second, we have worked at expressing randomly mutated Trm732 variants in a sick strain that lacks Trm732. Lack of rescue of the strain indicates that the mutation present is harmful to protein function. DNA from these colonies have been extracted and sequenced to determine the mutation that causes loss of Trm732 function. The human homolog for Trm732, THADA, has been linked to some forms of cancer and type II diabetes. The identification of Trm732 variants that cause loss of tRNA modification activity would help to determine how THADA is related to other diseases.