Concepts and Applications Eighth Edition Powerpoint Lecture Outline Human Genetics Concepts and Applications Eighth Edition Ricki Lewis Prepared by Dubear Kroening University of Wisconsin-Fox Valley

Chapter 11 Control of Gene Expression and Genome Architecture

Gene Expression Over Time Changes in gene expression may occur over time This may occur at the molecular, tissue, or organ gland level May be a response to environment

Globin Chain Switching Adult hemoglobin has four polypeptide chains Genes for alpha and beta subunits are located on chromosome 11 and 16 respectively Subunits change in response to oxygen levels Subunit makeup varies between embryo, fetus, and adult

Hemoglobin Composed of: Globular proteins Two alpha chains and two beta chains They surround an iron-containing heme group Figure 11.1

Globin Chain Switching Figure 11.2

Changing Gene Expression in Blood Plasma Blood plasma contains 40,000 different types of protein Changing conditions cause a change in the protein profile of the plasma Stem cell biology is beginning to shed light on how genes are turned on and off

Pancreas Exocrine and endocrine function Differential gene expression produces either endocrine or exocrine cells If transcription factor pdx-1 is activated, some progenitor cells follow the exocrine pathway Figure 11.3

Table 11.1

Differential Gene Expression Figure 11.4

Proteomics Uses analytical chemistry and microarrays to study all proteins produced Fourteen categories of proteins Variation in gene expression over lifespan and environment

Figure 11.5

Mechanisms of Gene Expression Transcription factors Promoter sequences (mutations) Copies of genes Histone code Histones play a major role in exposing DNA for transcription Important molecules: acetyl groups, methyl groups, and phosphates

Control of DNA Expression Figure 11.7

RNA Interference (RNAi) Transcription from DNA strand complementary to gene, bind to mRNA complements targeting them for removal Promotes gene silencing in the nucleus by methylating histones Removes certain mRNAs in the cytoplasm Biotechnology – gene “knock-down”

Figure 11.10

Figure 11.11

Proteins Outnumber Genes 1.5% of human genome encodes protein 25,000 genes specify up to 200,000 proteins Alternative splicing and cutting proteins translated from a single gene

Alternative Splicing within a Gene Figure 11.12

Dentinogenesis imperfecta Figure 11.13a Caused by deficiency in proteins DPP and DSP Both are cut from same larger protein

DPP and DSP Figure 11.13b

Majority of Human Genome Does not Encode Protein Rest of genome encodes for Viral DNA Noncoding RNAs Introns Promoters Other controls Repeats – transposons, telomeres, centromeres, pseudogenes, others

Table 11.4

Many companies are offering products based on RNA interference to use in research to "knock down" gene expression. Go to one of the following websites for the following companies, or find others. Research a particular RNAi product, and suggest how it might be used. (The companies listed have all existed for many years. There are many newer ones.) Ambion www.ambion.com Invitrogen www.invitrogen.com New England Biolabs www.neb.com Novagen www.novagen.com Qiagen www.qiagen.com Stratagene www.stratagene.com