Interaction of DNA and Proteins that Rec

목차

1. Interaction of DNA and Proteins that Recognize a Specific Base

2. TRANSLATION

3. Mutagenesis, Mutations, and Mutants

4. Plasmids

5. REGULATION of GENE ACTIVITY in PROKARYOTES

6. Regulation of Gene Activity in Eukaryotes

본문내용

omoter to stimulate the tanscription
- Transcription factors to stimulate house keeping genes ; constitutively active, their activities are regulated at posttranslational level.
- GR (glucocorticoid receptor) ; a steroid-inducible mammalian transcriptional factor
- In the absence of hormone, GR is complexed to the 90kD protein (hsp90) and locate in cytoplasm.
- When the steroid hormone (glucocorticoid) is diffused into the cell, it binds to the hormone binding domain of GR to cause the release of GR from hsp90. The release leads to the exposure of a nuclear translocation signal of GR.
- The transcription factor is, then, translocted into the nucleus via nuclear pore complex. In the nucleus, GR binds to its target sequence and stimulate transcrition of the GR-responsive genes.
- Yeat Gal4 ; remained in the nucleus, but inactive.
stimulate the gene expression of involved in the galactose metabolism.
- Gal4 always binds to its target DNA, but in the absence of galactose this can not stimulate the transcription due to the binding od Gal80 which disturb the Gal4 activity.
- Upon the addition of galactose, the Gal80 is released and Gal4 can stimulate transcription.
Gene Rearrangement: Joining of Coding Sequences in the Immune System
- The immune system of vetebrates is designed to offer a selective defense against all possible infectious agents, and to be ready even against those that appear on earth in the future.
- How ?
- Several million different protein molecules, immunoglobins or antibodies, are produced, whereby each can bind a distinct infectious taret molecules or antigen in a specific manner.
- If one gene codes for one antibody gene, the number of antiboddy gene (108) would exceed the estimated total number of human genes (105). --> Not realistic
- In general, a mature antibody-producing cell (B-lymphocyte) amkes only one type of antibody. So, there must be some mechanism that is responsible for programming each cell --> gene rearrangement
Different Immunoglobin Gene Segments
- IgG (immunoglobin G) ; one of several classes of immunoglobins, tetrameric protein containing two L chain and two H chains.
- Both L and H chains consist of two regions, the constant and variable region. The variabl region is is responsible for recognizing and binding a specific antigen. Two types of L chains; κ and λ. Both are similar in basic mechanism
- Three different classes of gene segments in L chain ; V, J, and C, which are located on the same chromosome
- About 300 different V gene-segments, 4 different J gene-segments, 1 copy in C gene-segment
- In embryonic cell, V segments form a tight cluster, J segments form a second cluster, and the C segment follows after J segment.
- Each V gene-segment is preceded by a promoter, and an enhancer is located between J and C segment (Fig 16-8).
- Gene rearrangement in which DNA is deleted between the particular V gene-segement and J gene-segment chosen for recombination. Many different combinations are possible.

키워드

DNA,   Mutagenesi,   Plasmids,   Mutations,   REGULATION