1Lecture 14: Genetic mutation•Multiple levels of gene regulations•Different types of mutations•Effects of mutations to gene expression and functions•What cause cancer?Regulation of gene expression at multiple levels
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21. Nuclear pore and nuclear transportNuclear pore structure contains 50-100 proteins called nucleoporins. In the cell, molecules smaller than ~60kD can diffuse freely through the nuclear pores, but those larger than 60kD cannot diffuse and they need selective transportation in or out of the nucleus.NLS: Nuclear Localization Signal of nuclear proteinsLarge nuclear proteins contain NLS. There are many different NLS sequences, often rich in basic amino acids. The SV40 NLS sequence, PKKKRLV, was the first one characterized. The NLS of a nuclear protein (X) can be fused, using recombinant DNA method, to a cytoplasmicprotein (Y) to force the recombinant Y move into the nucleus Native pyruvate kinaseis a cytoplasmic protein The pyruvate kinasefused to SV40-NLS is now in the nucleus