Transcript April 3 lecture slides

The genetic map of bacteriophage l
Control of transcription in bacteriophage l life cycle
by the anti-terminators N and Q proteins, the activator
CII protein and the repressor/activator CI protein
Characteristics of diploid with gal80, gal4,
and GAL81c mutations
Mutations affecting
galactose pathway in
yeast:
Genotype
Synthesis of
GAL1,GAL7,and GAL10
RNAs
Gal phenotype
gal80, GAL1/GAL80
GAL1
Inducible
+
gal4 GAL1/GAL4 GAL1
Inducible
(gal4/gal4  uninducible)
+
GAL81c GAL1/GAL81
GAL1
+
Constitutive
The steps and enzymes involved in the
utilization of the sugar galactose in the yeast
Saccharomyces
The transcriptional orientation of the 3 genes
coding for enzymes important in
galactose utilization in Saccharomyces
There synthesis is regulated by the transcription activator Gal4 protein.
GAL4 bound to DNA
A protein with a C6-zinc finger
(involves 6 cysteines)
Many
transcription
regulator proteins
have one (or
more) zinc-finger
domains
A retrovirus genome showing the location of
the transcription activation sites (enhancers)
The genome structure of mouse
mammary tumor virus is shown here
Analysis of genetic
regulation using
reporter gene
constructs
A transcription activator protein binds to the enhancer site and also interacts
with components of the RNA polymerase to achieve increased transcription
Enhancers and enhancerbinding proteins activate
transcription reminiscent of
the CAP site and CRP
activator protein in the lac
operon of E. coli.
A model for the structure of activator proteins bound
to 2 enhancers and RNA polymerase II bound to the
promoter and the interactions between them
Structures like this involving DNA with bound activator proteins and RNA
polymerase complex are names “enhanceosomes”. TBP stands for TATAbinding protein, a component of RNA polymerase II associated factor, TFIID
Uncovering of transcription protein binding sites
by chromatin remodeling complexes makes
binding by transcription-proteins possible
Use of alternative promoters at
different stages in life
Different promoters may be enhanced
depending upon which activator protein is
present in a cell
Alternative splicing
of the primary transcript
Structure of an immunoglobulin G (IgG)
molecule
The distribution of variable, joining and
constant sequences which are spliced to
create many different light chain proteins
Mating type switching during the life cycle
of some strains of Saccharomyces
Both mating type genes are located on chromosome III
of Saccharomyces. The mating type of the cell
is determined by the sequence present at the MAT site
Regulation of a-specific, a-specific and
haploid-specific genes in Saccharomyces
Three proteins (a1,
a1 and a2) are
involved in
regulating the
expression of these
3 classes of genes.
Cutting by methylcytosine sensitive/insensitive
restriction nucleases can be used to estimate the extent
of cytosine methylation in a DNA sequence
Imprinted genes in mammals
Table 2. Human imprinted genes and their mouse orthologues a (tab002gml)
Human
gene
Human
chromosome
Mouse
gene
Mouse chromosome
NOEY2, ARH1
1p31
p73
1p36.33
ZAC, PLAGL1
6q24
Zac1, Lot1
10
HYMA1
6q24.1-q24.3
IGF2R, M6PRb
6q25.3
Igf2r
17
GRB10, MEG1
7p11.2-p12
Grb10, Meg1
11
MEST, PEG1
7q32
Peg1, Mest
6
COPG2b
7q32
Copg2
6
WT1b
11p13
H19
11p15.5
H19
7
IGF2
11p15.5
Igf2
7
INS
11p15.5
Ins2, insulin II
7
ASCL2, HASH2
11p15.5
LTRPC5, MTR1
11p15.5
KCNQ1, KVLQT1
11p15.5
Kcnq1, Kvlqt1
7
p57KIP2
11p15.5
Cdnk1c, p57, Kip2
7
TSSC5, SLC22A1L
11p15.5
Orct12, Impt1, Itm, Tssc5, Bwscr1a
7
IPL, TSSC3
11p15.5
Tssc3
7
ZNF215
11p15.5
CDKN1C,
Some human diseases are due to loss of sites
involved in genomic imprinting
Alternative splicing of mRNA
Nonsense-mediated decay of
mRNA
Alt.splicing combined with NMD
can be used for genetic control
RNAi (RNA interference):
dsRNA directs degradation of mRNA with
the same/complementary sequence
Translational
control