Lecture 5

Question 1

What is the median eminence?

Answer 1

An area of the brain’s circulation that lies close to the third ventricle. There is no blood-brain barrier here.

Question 2

What is meant by a ‘radial glial-like appearance’ in terms of hypothalamic stem cells?

Answer 2

The cell body sits close to the lumen (the third ventricle) and sends out a projection (to the arc nuc) that acts as a scaffold.

Question 3

What is the role of islet 1 in hypothalamic stem cells maintenance?

Answer 3

Islet 1 expression is detected just before pomc expression. Isl1 binds to pomc enhancers to upregulate the expression of pomc/differention of POMC neurons. Conditional Isl1 inactivation impairs pomc expression.

Question 4

Explain how to carry out lineage tracing

Answer 4

Tg1: CreERT2 downstream of a cell-specific promotor. (CreERT2 is a cre-recomb fused to estrogen ligand-binding domain that req tamoxifen for activation.
Tg2: stable reporter downstream of ubiq promotor but separated by floxed STOP seq
Cross the lines, add tamoxifen and the stop seq will be recomb out and reporter will expressed in cell and it’s daughters

Question 5

Does FGF2 stimulate the proliferation of tanycytes?

Answer 5

Yes, FGF1 also does the same

Question 6

Can FGF be used to induce remission of T2D?

Answer 6

Yes, studies in rodents have found that central injection of FGF1 induces sustained remission of T2D. There is no effect on the peripheral tissues and so it is hypothesised that the FGF is stimulating the neurons that control feeding behaviours (pomc/NPY neurons)