Lecture 17 Class: Gene Regulation
Starter:
Alternative Splicing
Definition:
A UCI grad student named Lauren studies a transcription factor called Ovol2 that is required for
normal mouse mammary gland development. Ovol2 is a single gene, yet there are three distinct
Ovol2 variants expressed at the protein level. Which of the following best explains this
phenomenon?
A. Alternative splicing of the Ovol2 mRNA
B. Alteration of the Ovol2 transcript by microRNAs
C. Frameshift mutations in the Ovol2 gene sequence
D. Ovol2 is recognized and degraded by a proteasome
E. Exons are not spliced out of the Ovol2 transcript
Lecture 17 Page 1
Meiosis disorders that affect the sex chromosomes:
Turner syndrome:
 One X chromosome ( _____________).
 Female, sterile, other health issues
Kleinfelter syndrome:
 Extra X chromosome ( _____________)
 Male, often reduced fertility, minimal health problems.
SRY Transcription Factor

The SRY gene codes for an SRY _______________________________________ that
turns on the SOX9 gene.

The SOX9 gene codes for a SOX9 transcription factor that turns on the genes for
______________ development.
XX Male Syndrome:
X Chromosome
X Chromosome
The SRY gene has moved from Y chromosome to X by a ________________________ mutation.
Testes development
Lecture 17 Page 2
Swyer Syndrome (XY Females):
X Chromosome
X
Chromosome
Mutation
or loss of SRY on the Y choromosome
No testes development
The SRY gene codes for a transcription factor that triggers testes development and also
regulates dopamine production. Based on this, you would expect SRY mutations to more often
cause dopamine-related diseases like schizophrenia to be more common in:
A. Women
B. Men
P53 and Cancer
A Healthy cell
Lecture 17 Page 3
A Stressed cell
A mutation in p53 allows uncontrolled mitosis.
Lecture 17 Page 4
In normal cells, a growth factor activates a G protein called RAS that turns on a transcription
factor that stimulates the cell cycle. In a cancer cell, you would expect:
A. The growth factor to bind to the DNA itself
B. An over-expression of proteins that inhibit the cell cycle
C. An increase in miRNA that target cell cycle stimulation genes
D. The G protein to be overactive
Lecture 17 Page 5