武汉大学：《遗传学》课程教学课件（英文讲稿）Chapter 11 The Eukaryotic Chromosome

Chapter 11The Eukaryotic Chromosome13-1

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-1 The Eukaryotic Chromosome The Eukaryotic Chromosome Chapter 11 Chapter 11

Sectionsto study11.1ChromosomalDNAandproteins11.2 Chromosome structure and compaction11.3Chromosomalpackaging and gene expression11.4Replication of eukaryotic chromosomes11.5Chromosomesegregation1l.6Artificialchromosomes13-2

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-2 Sections to study Sections to study 11.1 Chromosomal DNA and proteins 11.1 Chromosomal DNA and proteins 11.2 Chromosome structure and compaction 11.2 Chromosome structure and compaction 11.3 Chromosomal packaging and gene expression 11.3 Chromosomal packaging and gene expression 11.4 Replication of eukaryotic chromosomes 11.4 Replication of eukaryotic chromosomes 11.5 Chromosome segregation 11.5 Chromosome segregation 11.6 Artificial chromosomes 11.6 Artificial chromosomes

Chromosome-The self-replicating genetic structures of cellscontaining the DNA that carries in its nucleotide sequence thelineararrayofgenes二果S36789101112341EB8828a5131415161718STHumanchromosomes19202122V十Humanmalekaryotype13-3

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-3 Human chromosomes Human male karyotype Chromosome Chromosome − The self The self-replicating genetic structures of cells replicating genetic structures of cells containing the DNA that carrie containing the DNA that carries in its nucleotide sequence the s in its nucleotide sequence the linear array of genes. linear array of genes

HEN:DecIsiontoduplicated?duplicateChromosomesTHEN:Decisionchromosomesandto entermitosischange shape andcentrosomesposition duringthe cell cycleProphaseMitosisInterphaseCOngoingproteinsynthesisMetaphaseandcellgrowthHave all.Telophase1chromosomesandarrived andcytokinesisaligned attheAnaphasemetaphaseplate?13-4

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-4 Chromosomes change shape and position during the cell cycle

Chromatin（染色质）-ThegenerictermforanycomplexofDNAand protein foundin a cell's nucleusChromonemafiberLinkerhistonesNLong rangefiber-fiberShortrangeinteractionsinternucleosomainteractions30nmfiberG1chromatidBeads-on-a-stringNucleosomeCore histoneDNANtail domain13-5

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-5 Chromatin Chromatin (染色质)− The generic term for any complex of DNA The generic term for any complex of DNA and protein found in a cell and protein found in a cell’s nucleus. s nucleus

11.1 ChromosomalDNA and proteinsThechromatinisroughly1/3DNA,1/3histones,and1/3nonhistone proteins by weight.Each chromosomepackages a singlelong moleculeofDNAStudies examine stretching and recoiling of chromosomes.Longerpieces recoil more slowly than shorter pieces.Pulse field gel electrophoresis (PFGE)Separates large pieces ofDNA-numberand sizes correspond tonumberand sizes expectedifeach chromosomecontains a singlepieceofDNA13-6

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-6  The chromatin is roughly 1/3 DNA, 1/3 The chromatin is roughly 1/3 DNA, 1/3 histones histones, and 1/3 , and 1/3 nonhistone nonhistone proteins by weight. proteins by weight.  Each chromosome packages a single long molecule of DNA. Each chromosome packages a single long molecule of DNA.  Studies examine stretching and recoiling of chromosomes. Longer Studies examine stretching and recoiling of chromosomes. Longer pieces recoil more slowly than shorter pieces. pieces recoil more slowly than shorter pieces.  Pulse field gel electrophoresis (PFGE) Pulse field gel electrophoresis (PFGE)  Separates large pieces of DNA Separates large pieces of DNA – number and sizes correspond to number and sizes correspond to number and sizes expected if each chromosome contains a single number and sizes expected if each chromosome contains a single piece of DNA piece of DNA 11.1 Chromosomal DNA and proteins 11.1 Chromosomal DNA and proteins

Pulse field gel electrophoresis (PFGE)S.pomboScerevislae83chr16chr2.450-5,580kb300-2.000kbeach13-7

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-7 Pulse field gel electrophoresis (PFGE) Pulse field gel electrophoresis (PFGE) 3 chr 2,450-5,580 kb 16 chr 300-2,000 kb each

Protein componentsofchromosomesHistone proteins abound the chromatin of all eukaryotic cellsHistones-small proteins with basic,positively charged amino acidslysineandarginineBind to and neutralizenegatively charged DNA.Make uphalf ofall chromatinprotein by weight.1MARTKQTARKSTGGKAPRKQLASKAARKSAPSTGGVKKPHRYKPGTVALR51EIRRFQKSTELLIRKLPFQR LVREIAQDFKTDLRFQSSAIGALQESVEAY101LVSLFEDTNLAAIHAKRVTIQKKDIKLARRLRGERS*Yeast histone H3 (Hht1)13-8

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-8 Protein components of chromosomes Protein components of chromosomes  Histone Histone proteins abound the chromatin of all eukaryotic cells. proteins abound the chromatin of all eukaryotic cells.  Histones Histones – small proteins with basic, positively charged amino acids small proteins with basic, positively charged amino acids lysine and lysine and arginine arginine.  Bind to and neutralize negatively charged DNA. Bind to and neutralize negatively charged DNA.  Make up half of all chromatin protein by weight. Make up half of all chromatin protein by weight. Yeast histone H3 (Hht1)

Histone proteinsDNAFive types: H1, H2A, H2B, H3, and H4.Core histones make up nucleosome:H2AH2BH2A,H2B,H3,andH4NucleosomeDNA and histone synthesis regulationcorrelate timing so both are synthesizedH4H3together.Evolutionarily conservedCoreof8Histonesasi13-9

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-9  Histone Histone proteins proteins  Five types: Five types: H1, H2A, H2B, H3, and H4.  Core histones histones make up make up nucleosome nucleosome: H2A, H2B, H3, and H4. H2A, H2B, H3, and H4.  DNA and DNA and histone histone synthesis regulation synthesis regulation correlate timing so both are synthesized correlate timing so both are synthesized together. together.  Evolutionarily conserved. Evolutionarily conserved

Post-translational modification ofhistonesAcetylationModificationsitesMethylation品PhosphorylationH3DNAH2AAAAH4H2BARTKOTARKSTGGKAPRKOLATKAARKSAHistoneHistonetail89.1014PPMNucleosomePossiblemodification of amino acidsatthe Nterminus ofyeasthistoneH3Fig.11.1313-10

Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 13-10  Post-translational modification of translational modification of histones histones  Acetylation Acetylation  Methylation Methylation  Phosphorylation Phosphorylation Possible modification of amino acids at the N￾terminus of yeast histone H3 Fig. 11.13