BCOR 103 1st Edition Lecture 21 Outline of Last Lecture I Regulation of Transitions II Meiosis III Stem Cells Outline of Current Lecture I Nuclear Structure and Function II Components III Transport Current Lecture Components o Nuclear Envelope Two lipid bilayers In between membranes is perinuclear space o NPC Nuclear Pore Complex Only way in and out of the nucleus with the exception of hydrophobic steroid hormones hydrophobic steroid hormones can diffuse across the membrane o Nucleolus ribosome production o Light Dark areas in transmission electron micrograph heterochromatin euchromatin Light not condensed euchromatin is expressed Dark condensed heterochromatin no expressed Chromatin DNA and associated proteins o 30nm filaments o DNA alone is 2 nm Nucleosomes o Key function package DNA o 147 base pairs wrap around a nucleosome 1 75 times Protamines o Help neutralize charge on DNA so it can be packaged These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Spermatids don t express genes so genome can be condensed Histones o Amino terminal tails reversible translation modifications o Flexible o 30 of protein Histone Code o Can be read o Written by writer proteins Outer Membrane of nuclear envelope is contiguous with endoplasmic reticulum Nuclear Lamina o Meshwork of proteins and intermediate filaments that provides structural support for the nucleus Prenylation targets lamins to inner nuclear membrane o Prenyl group is 15 carbons long with a cysteine head o After Lamin A and Lamin C groups are inserted the prenyl group are removed o Doesn t happen with Lamin group B Hutchinson Gilford Progeria Syndrome o Lamins A and C mutations dominant negative deletion removal of prenyl groups doesn t occur o Nuclear morphological abnormalities o Age 8 10X faster o Disorganization of heterochromatin o Defective repair of DNA damage and increased genomic instability o Drug that helps inhibitor of farnesyl transferase initially cancer drug Transport into and out of the nuclear membrane by the NPC o 30 proteins o Requires energy o Is selective o Receptor Proteins In importin Out exportin o RAS Family of small GTP binding proteins bound to GDP off GTP on
View Full Document
Unlocking...