Protein kinases are an abundant class of enzymes which play important roles in numerous signal transduction systems. Arabidopsis TOUSLED kinase is a serine/threonine kinase which is essential for cell-cell communication within the shoot meristem. TOUSLED is encoded by a single gene in Arabidopsis. Recessive mutants in this gene show mild vegetative defects and severe floral abnormalities including a random reduction in the number of floral organs produced and defects in the formation of the gynoecium.
This thesis describes the cloning and characterization of three maize genes with homology to TOUSLED. These genes are known as the TOUSLED-LIKE KINASE (TLK) genes. Partial genomic and cDNA clones of the maize TLK genes have been sequenced and analyzed. These genes show remarkable similarity to each other and to TOUSLED over the region corresponding to the TOUSLED catalytic domain. The TLK genes fall into two distinct classes on the basis of nucleotide and amino acid sequence. Both classes appear to be expressed throughout the plant. In addition, database searches reveal that TOUSLED-like genes are present in a diverse array of other eukaryotes, indicating that the TLK genes are members of a widespread, evolutionarily conserved class.
Two approaches have been taken to find mutants in the TLK genes. This thesis describes the tassel-less1 (tls1) mutant, a possible mutant in one of the TLK genes. The tls1 mutation maps to the same chromosomal location as one of the TLK genes, and may represent a lesion in this TLK gene. Characterization of the t1s1 mutant reveals that disruption of the TLS1 gene results in variable, progressive vegetative defects and severe reduction of the reproductive structures. The tls1 phenotype is consistent with the hypothesis that TLS1 plays a role in regulating meristem activity. In addition, TLK sequences have been used in a reverse genetics screen to isolate families which contain Mutator transposable element insertions into the TLK genes. These families are currently being analyzed for phenotype and allelism to tls1. / Graduation date: 1997
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34358 |
| Date | 01 May 1997 |
| Creators | Yoon, Elizabeth S. |
| Contributors | Rivin, Carol J. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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