Thesis Title

Transgenic Plants, Current State, and Influence on the Environment


Xian Xie

Date of Graduation

Summer 1998


Master of Science in Biology



Committee Chair

John Steiert

Subject Categories



Hydra vulgaris, a fresh water cnidarian, was used in this study of extracellular matrix (ECM) molecular functions at the genetic level. To clone ECM genes, screening of a hydra cDNA library was accomplished by using a laminin A chain sequence obtained from polymerase chain reaction as a probe. A clone, 1am A1, was sequenced and characterized in this project. In situ hybridization studies indicated that the laminin A chain messenger RNA is located in the endoderm. A high level of expression is observed at the base of the tentacles, which indicates that the ECM molecule, laminin, may participate in the patterning process of hydra tentacles, cell migration, and cell differentiation processes of nematocytes. Decapitation and regeneration studies indicated that the range of expression of laminin A chain along the tentacles varies at different regeneration stages, from the entire length of tentacles at early stages to the base of tentacles when they reach the mature stage. The expression pattern change suggests control factors related to the maintenance of the tentacle branching mechanism or to the cell differentiation and cell migration processes.


© Xian Xie