Gene clusters are formed by duplication and divergence Sequence divergence is the basis for the evolutionary clock Pseudogenes are dead ends of evolution Unequal crossing-over rearranges gene clusters Genes for rRNA form tandem repeats ( The repeated genes for rRNA maintain constant sequence) Crossover fixation could maintain identical repeats Satellite DNAs often lie in heterochromatin Arthropod satellites have very short identical repeats Mammalian satellites consist of hierarchical repeats Minisatellites are useful for genetic mapping
28.1 Introduction 28.2 Transforming viruses carry oncogenes 28.3 Early genes of DNA transforming viruses have multifunction oncogenes 28.4 Retroviruses activate or incorporate cellular genes 28.5 Retroviral oncogenes have cellular counterparts 28.6 Ras oncogenes can be detected in a transfection assay 28.7 Ras proto-oncogenes can be activated by mutation at specific positions 28.8 Nondefective retroviruses activate proto-oncogenes 28.9 Proto-oncogenes can be activated by translocation 28.10 The Philadelphia translocation generates a new oncogene 28.11 Oncogenes code for components of signal transduction cascades 28.12 Growth factor receptor kinases can be mutated to oncogenes 28.13 Src is the prototype for the proto-oncogenic cytoplasmic tyrosine kinases 28.14 Oncoproteins may regulate gene expression 28.15 RB is a tumor suppressor that controls the cell cycle 28.16 Tumor suppressor p53 suppresses growth or triggers apoptosis
26.1 Introduction 26.2 Carriers and channels form water soluble paths through the membrane 26.3 Ion channels are selective 26.4 Neurotransmitters control channel activity 26.5 G proteins may activate or inhibit target proteins 26.6 G proteins function by dissociation of the trimer 26.7 Growth factor receptors are protein kinases 26.8 Receptors are activated by dimerization 26.9 Receptor kinases activate signal transduction pathways
25.1 Introduction 25.2 Oligosaccharides are added to proteins in the ER and Golgi 25.3 The Golgi stacks are polarized 25.4 Coated vesicles transport both exported and imported proteins 25.5 Different types of coated vesicles exist in each pathway 25.6 Cisternal progression occurs more slowly than vesicle movement 25.7 Vesicles can bud and fuse with membranes 25.8 SNAREs control targeting 25.9 The synapse is a model system for exocytosis 25.10 Protein localization depends on specific signals 25.11 ER proteins are retrieved from the Golgi 25.12 Brefeldin A reveals retrograde transport 25.13 Receptors recycle via endocytosis 25.14 Internalization signals are short and contain tyrosine
