BIOL 200 Lecture Notes - Lecture 8: Histone H2A, Heterochromatin, Histone H2B
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Without nls fluorescence in cytosol only. With nls, all fluorescence entirely in nucleus, so nls leads to movement into nucleus. Mutated nls fluorescence restricted to cytosol: draw conclusions. Based on three proteins, nls is required for nuclear membrane transport. Nls is sufficient enough to get into nucleus. Mutated nls protein no longer able to access nucleus. Particular nucleotide sequence is crucial for nuclear transport. ** presence of nls is sufficient/required for nuclear import. ** loss of nls (as in 3) or absence of nls (as in 1 ) demonstrates it was necessary for import. ** nls -> exposure required, for it to get recognized by receptor and bind. Tips: observe/describe, use knowledge to make conclusion. Q: once a protein containing an nls is imported into the nucleus, the nls is cleaved off because it is no longer needed. A: could be required for something else later. Nls is retained by the nuclear proteins (not cleaved upon transport) (ex.
