Lecture 25

Question 1

Which three transcription factors are absolutely required for the formation of the nephric duct

Answer 1

Lim1, Pax8 and Pax2

Question 2

From what two structures does the kidney develop from and which mesodermal tissue are these structures derived from

Answer 2

Nephrogenic cord and nephrogenic duct – derived from the intermediate mesoderm

Question 3

As too much six2 expression prevents differentiation and too little leads to a depletion of the stem cell pool it is essential that only an intermediate level of its expression occurs to induce the creation of the two daughter cells required in nephrogenesis, T or F

Answer 3

T

Question 4

What is the results of overexpression of the six2 transcription factor

Answer 4

Prevention of differentiation

Question 5

What structures in the adult does the mammalian pronephros give rise to

Answer 5

Although the pronephros gives rise to the pronephric duct and pronephric cord, the later degenerates with the anterior pronephric duct

Question 6

As the nephrogenic duct extends caudally, what structures does it induce the formation of in the nephrogenic cord

Answer 6

Nephric tubules

Question 7

What structure does the pronephric duct join with as it extends caudally

Answer 7

Cloaca

Question 8

Ultimately the kidney develops from the metanephric mesenchyme, from which structure is this tissue formed from

Answer 8

Nephrogenic cord

Question 9

Most likely different Hox code or signals from the cloaca mediate the formation of the kidney proper/metanephros, T or F

Answer 9

T

Question 10

As well as six2 acting as a marker for the identification of nephron stem cells, what other role does it play

Answer 10

Six2 acts to maintain the nephron stem/progenitor cells by keeping them self-renewing

Question 11

Lecture 24 Question 1 - See table

Answer 11

c, a, b, d

Question 12

A remnant of the initial ureteric bud will from what structure in the adult

Answer 12

The ureter

Question 13

Stem cells of the ureteric bud and metanephric mesenchyme are retained into postnatal life, T or F

Answer 13

T

Question 14

Branching morphogenesis of the ureteric bud underlies the future nephrons, T or F

Answer 14

F – it underlies the prospective calyces

Question 15

Which cell adhesion molecules are identifiable markers of the nephric duct and can be observed to compare the effects of Pax2 and Pax8 knockout

Answer 15

Laminin and E-cadherin

Question 16

What structures in the adult does the mammalian mesonephros give rise to

Answer 16

The mesonephros along with the most caudal pronephric duct (from the pronephros) give rise to the Wolffian duct

Question 17

The ureteric bud forms from the most causal region of the nephric duct, T or F

Answer 17

T

Question 18

Describe the anatomical relations of the nephric duct and nephric cord

Answer 18

Nephric duct lies dorsally to the nephric cord and elongates in a rostral caudal direction

Question 19

Six2 positive cells are nephron precursor cells that will undergo what type of change in cell behaviour

Answer 19

MET cell transition

Question 20

What is seen at the level of the renal pelvis

Answer 20

Where the ureter ends and the where the branches of the major calyces begin

Question 21

What gene first expressed in the intermediate mesoderm prior to kidney development was initially discovered in a paediatric kidney cancer where kidney elements are incompletely differentiated and proliferate to form tumours

Answer 21

Wilms tumour 1 (Wt1)

Question 22

The transcription factor Six2 can be used to identify stem cells of the nephron, what experimental evidence is there for this

Answer 22

Genetic lineage tracing has been used to determine that six2 positive cells give rise to cells of the nephron. These have involved the creation of transgenes with GFP fused to the six2 coding region and under the control of its promoter.

Question 23

In mammals, the posterior nephric tubules degenerate and undergo apoptosis, T or F

Answer 23

F – In mammals, anterior structures degenerate, leaving only metanephric regions

Question 24

Which paired box transcription factor is expressed by the nephric duct

Answer 24

Pax2

Question 25

Outline the development of the mesonephros

Answer 25

As the pronephric tubules degenerate, the middle portion of the nephric duct induces a new set of kidney tubules in the mesenchyme. These new kidney tubules constitute the mesonephros or mesonephric kidney. Each mesonephric tubule attracts a blood supply from a branch of the nearby aorta which end in a capillary tuft – analogous to the glomerulus of the definitive nephron. Mesonephric tubule forms a capsule around this tuft, allowing for blood filtration

Question 26

Older nephrons are found in the inner regions of the kidney and the newer ones are found at the periphery, T or F

Answer 26

T

Question 27

What structures in the adult does the metanephros give rise to

Answer 27

The metanephros gives rise to the kidney proper

Question 28

What type of cells are contained in the intermediate mesoderm

Answer 28

Mesenchymal cells

Question 29

What is the result of a conditional knockout/loss of six2 expression

Answer 29

Depletion of the nephron stem cell pool

Question 30

Discuss the ultimate fate of the mesonephros

Answer 30

The mesonephros largely generates, However, in males, some tubules retained and form vas deferens. But by now, the metanephric (definitive) kidney has been induced

Question 31

Which structure expresses wt1 involved in kidney development

Answer 31

Nephric cord

Question 32

Kidney development is protracted, proceeding throughout prenatal and even into postnatal life, T or F

Answer 32

T