Bulletin Spring‧Summer 1994

From Your Very Heart Two novel genes found in the human heart A Matter of the Heart The human heart has always been regarded as the seat of emotions. In fact, it is nothing but a very rugged pump that can often work for close to a century. Nevertheless, the pump does run into problems very often. With infectious diseases increasingly under control, cardiovascular diseases have become the major cause of death and disability after age 35. In order to deal effectively with cardiovascular diseases, researchers set out to investigate their nature and wha t constitutes predisposition to heart diseases. Whereas in the past such investigations were largely dependent on the study of gross anatomy and physiology, over the last few decades medical scientists have adopted a much more microscopic and fundamental approach, which is expected to be more fruitful. How Genes Come into Play Many diseases have some genetic component. Some diseases, such as sickle-cell anaemia, are caused by a change in a single base in the DNA. However, most genetically influenced diseases, including heart diseases, are more complex; they are caused by flaws in several genes. A thorough study of the genes involved in the heart is therefore required to understand the genetic basis o f heart diseases. Humans are believed to have about 100,000 genes in their DNA. A gene is a kind of computer code, written by chemical bases that stretch along part of the double-helix DNA molecule. The code in a gene orders the cell to produce one and only one type of protein. Fortunately, not all 100,000 genes are expressed in the heart; typically only 10,000 to 30,000 are expressed in any one kind of tissue. So by systematically studying the 10,000 to 30,000 genes involved in the heart, it is hoped that a better set of molecular tools will be acquired for fighting heart diseases. As a possible bonus, the results might allow doctors to tell whether treatments are effective, by monitoring the genes that are expressed aberrantly. Discovery of New Genes A group of researchers led by Dr. Mary Way e and Prof C.Y. Lee of the Department of Biochemistry are currently engaged in such systematic studies at The Chinese University of Hong Kong. They enjoy the support of overseas collaborators, includin g Prof. C.C. Liew of the University of Toronto and hi s research assistants. The project started i n 1992 with very little manpower and equipment, but in 1993, a grant of HK$766,600 was obtained from the Research Grants Council for a period of two years, and amachine crucial for the project—the automatic DNA sequencer — was purchased. The project gradually gained momentum and by early 1994 was able to produce results. The first stage of the project involved a systematic approach to identify all novel genes expressed in heart tissue. To do this, a library of cDNA clones relevant to the human heart was first obtained. A cDNA is a complementary DNA artificially produced from mRNA molecules taken from the heart. These cDNAs are then inserted into th e DNA of bacteriophage lambda, which is a virus o f bacteria. The recombinant materials that grow out of such a process are called 'clones' . The library of cDNA clones contain at least one DNA copy of each of the Amplification and purification of human heart cDNA clones for sequence analyses Research Projects 19