9304974 Timko Chlorophylls, hemes, and their derivatives play an important role in the energy absorption and transduction processes of all photosynthetic organisms. The laboratory has isolated and characterized members of three nuclear gene families that encode enzymes of the tetrapyrrole biosynthetic pathway. There are three objectives desired. The first objective is to understand how cells regulate the coordinate formation of the various tetrapyrrole biosynthetic pathway enzymes in a developmental and cell specific manner. The second objective is to define the similarities and differences in the regulatory mechanisms controlling the expression genes encoding protochlorophyllide reductase in angiosperms (pea) and gymnosperms (pine). In order to meet these objectives, more effort will continue on current studies examining how the formation and intracellular distribution of these enzymes are regulated, the nature of the transcriptional or post-transcriptional of processes that control them change in response to alterations in cell physiology or environment. These studies will provide important new information on the structure, function, and expression of enzymes involved in one of the most fundamental processes in plants. %%% Chlorophylls and similar molecules play an important role in the ability of plants to absorb light energy and transduce the energy into food and biomaterials. The researchers have isolated and characterized three gene families that code for the enzymes that produce chlorophyll and other similar molecules. There are three objectives desired. The first objective is to understand how cells produce the right amounts of the enzymes during the life of the plant and in different parts of the plant. The second objective is to see what is similar and different in the genetic control of one particular enzyme in peas and pine trees. More work on current studies examining how the formation and intracellular distribution of these enzyme s is regulated by different processes will continue. These studies will provide important new information on the structure, function, and expression of enzymes involved in one of the most fundamental processes in plants. ***
