Download early blastocyst

BBio 351 – November 5, 2015
Today’s outline
• Finish reproduction!
• Finish slides from 10-29-15
• Making a person: from zygote to gastrula
• Early embryogenesis
• The 2nd week of life
• Hasuwa (2013): MiR-200b and miR-429 Function in
Mouse Ovulation and Are Essential for Female
Fertility
Making a person: from zygote to gastrula
• POGIL-style activity taken from Anatomy & Physiology: A
Guided Inquiry by Patrick J.P. Brown
• Work through questions in teams…
• …then face “challenge questions”!
Model 1: early embryogenesis
Sherwood Figure 16-22
Model 1 questions
1. Once the oocyte joins with a sperm, the new diploid cell has a new name (not
listed in the figure). What is this term?
a. What is the name of the process that produces this cell?
2. Within the first 2 days, the diploid cell divides twice. How many cells will there be
after 2 rounds of division?
a. What do you think the term “cleavage” means here?
3. What is the embryo called once it has become a solid ball of 16 or more cells?
4. On Day 5, the early blastocyst hatches. From what structure does it hatch (i.e.,
what does the blastocyst emerge from)?
Patrick J.P. Brown
Model 1 questions
5. What is the name of the single layer of cells that completely surrounds the
blastocyst?
a. What other component of the blastocyst is labeled?
b. The blastocoel is NOT labeled. Look up what “coel” means,
then label the blastocoel in the figure.
6. The early blastocyst forms at about Day 5. What major event takes place
between Day 5 and Day 7?
a. In what case would this major event NOT take place?
Patrick J.P. Brown
Challenge question(s)
Model 2: the 2nd week of life
Patrick J.P. Brown
Model 2 questions
8. According to the model, what structure grows from the trophoblast into the
surrounding uterine (endometrial) tissue?
a. What cavity is beginning to open up between the trophoblast and the
inner cell mass at this time?
9. By Day 11, there are 2 spaces inside the embryo: 1 cavity and 1 sac. List them.
a. In addition to the formation of these two cavities, another important
event occurs during gastrulation. List the 3 germ layers that are formed
during gastrulation and an example of a body tissue derived from each
layer.
b. What does gastrulation mean?
Patrick J.P. Brown
Model 2 questions
10. All of the body’s tissues and organs derive from these 3 germ layers. What
structure in the early blastocyst gave rise to these 3 germ layers?
a. Do the trophoblast, amnion, or yolk sac appear to develop into any
tissues that will be found in the child at birth?
b. Why are these called extraembryonic tissues?
11. Cardiac and renal defects often occur together in newborns, as do skin and
nervous disorders. As a group, explain why these (and other) birth defects often
occur together.
Patrick J.P. Brown
Challenge question(s)
Challenge question(s)
Reproduction paper: H. Hasuwa et al., Science 2013
• Review: hypothalamic-pituitary-gonadal axis
• How exactly does GnRH promote LH secretion?
• Review: control of gene expression
What are microRNAs (miRNAs)?
Stefanie S. Jeffrey, Nature Biotechnology 2008
Genetic tools/tricks: reporter assay to see how
miR-200b & miR-429 affect Zeb1 expression
Hasuwa et al. (2013), Figure S13
Genetic tools/tricks: Zeb overexpression
Google Images search results;
Hasuwa et al. (2013), Figure 3B-C
Reproduction paper: H. Hasuwa et al., Science 2013
• Fig. 1. Infertility phenotype of miR-DKO mice.
• Fig. 2. Pituitary defects in miR-DKO female mice.
• Fig. 3. Lhb expression is regulated by ZEB1 as a
potential target of miR-200b and miR-429.
Fig. 1. Infertility phenotype of miR-DKO mice.
Hasuwa et al. (2013), Figure 1A
Fig. 1. Infertility phenotype of miR-DKO mice.
Hasuwa et al. (2013), Figure 1C-F
Fig. 2. Pituitary defects in miR-DKO mice.
Hasuwa et al. (2013), Figure 2A-D
Fig. 2. Pituitary defects in miR-DKO mice.
Hasuwa et al. (2013), Figure 2E-H
Fig. 3. Lhb expression is regulated by ZEB1 as a
potential target of miR-200b and miR-429.
Hasuwa et al. (2013), Figure 3D-E
Diagram to summarize main findings?
What questions could be researched next?