Lecture 19 Development and cancer “The inner life of a cell”
Four essential processes by which a multicellular organism is made
Basic anatomical scheme common to all animals exemplified here by sea urchin gastrulation Gastrulation: the transformation of a simple ball or hollow sphere of cells into a structure with a gut--an almost universal feature of animal development Ectoderm: epidermis and nervous system Endoderm: gut (lung and liver) Mesoderm: muscle, connective tissues..
Conjoined (Siamese) twins Striking results from experimental embyrology
Two ways of making sister cells different
The emergence of cell diversity Lateral inhibition (short-range) Inductive interaction Some short-range Others long-range
Morphogens are long-range inducers Sonic hedgehog The polarizing reion
The lineage tree for the cells that form the gut of C. elegans
Drosophila melanogaster A homeotic mutation Antennapedia mutant Antennae are converted into leg structures
The Hox complex of insect and the Hox complexes of a mammal
Neural crest cells migrate in specific pathways and give rise to many cell types (including skin pigment cells)
Effect of kit gene mutation Pigmentation is defective because pigment cells depend on the kit gene product to for a survival factor
Nodal is expressed on the left side Some infertile men (dynein mutation mutation--cilia and flagella beating) Left-right organs inverted
Three phases of neural development
Benign Malignant Carcinomas:epithelial cells Sarcomas: connective tissues or muscle cells Leukemias: hemopoitic cells Cancers in the nervous system Terms The common sites in the bone marrow for metastasis of the prostate cancer
Cancer incidence and mortality in the United States Year 2000 The fiive most common types: lung, stomach, breast, colon/rectum, uterine cervix 6 million new cases a year in the whole world
The normal and deranged control of cell production from stem cells
Viruses contribute a significant proportion of human cancers
The major signaling pathways relevant to human cancer
Suggested typical sequence of genetic changes underlying the development of a colorectal carcinoma Steps of tumor pregression
Summary 1.The question of developmental biology is how linear genetic information encoded in DNA sequence determines the formation of 3-D structures of a multicellular organism; 2Developmental processes are highly conserved and anatomical schemes are highly similar in animals; 3Mechanisms of cell diversity, tissue morphogenesis; 4Model organisms; 5Cell migration; 6Nervous system development--circuits; 7Cancer, cancer research and biology, causes of cancer and a continuing battle…