Lecture 25 Flashcards
Which three transcription factors are absolutely required for the formation of the nephric duct
Lim1, Pax8 and Pax2
From what two structures does the kidney develop from and which mesodermal tissue are these structures derived from
Nephrogenic cord and nephrogenic duct – derived from the intermediate mesoderm
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
T
What is the results of overexpression of the six2 transcription factor
Prevention of differentiation
What structures in the adult does the mammalian pronephros give rise to
Although the pronephros gives rise to the pronephric duct and pronephric cord, the later degenerates with the anterior pronephric duct
As the nephrogenic duct extends caudally, what structures does it induce the formation of in the nephrogenic cord
Nephric tubules
What structure does the pronephric duct join with as it extends caudally
Cloaca
Ultimately the kidney develops from the metanephric mesenchyme, from which structure is this tissue formed from
Nephrogenic cord
Most likely different Hox code or signals from the cloaca mediate the formation of the kidney proper/metanephros, T or F
T
As well as six2 acting as a marker for the identification of nephron stem cells, what other role does it play
Six2 acts to maintain the nephron stem/progenitor cells by keeping them self-renewing
Lecture 24 Question 1 - See table
c, a, b, d
A remnant of the initial ureteric bud will from what structure in the adult
The ureter
Stem cells of the ureteric bud and metanephric mesenchyme are retained into postnatal life, T or F
T
Branching morphogenesis of the ureteric bud underlies the future nephrons, T or F
F – it underlies the prospective calyces
Which cell adhesion molecules are identifiable markers of the nephric duct and can be observed to compare the effects of Pax2 and Pax8 knockout
Laminin and E-cadherin
What structures in the adult does the mammalian mesonephros give rise to
The mesonephros along with the most caudal pronephric duct (from the pronephros) give rise to the Wolffian duct
The ureteric bud forms from the most causal region of the nephric duct, T or F
T
Describe the anatomical relations of the nephric duct and nephric cord
Nephric duct lies dorsally to the nephric cord and elongates in a rostral caudal direction
Six2 positive cells are nephron precursor cells that will undergo what type of change in cell behaviour
MET cell transition
What is seen at the level of the renal pelvis
Where the ureter ends and the where the branches of the major calyces begin
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
Wilms tumour 1 (Wt1)
The transcription factor Six2 can be used to identify stem cells of the nephron, what experimental evidence is there for this
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.
In mammals, the posterior nephric tubules degenerate and undergo apoptosis, T or F
F – In mammals, anterior structures degenerate, leaving only metanephric regions
Which paired box transcription factor is expressed by the nephric duct
Pax2
Outline the development of the mesonephros
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
Older nephrons are found in the inner regions of the kidney and the newer ones are found at the periphery, T or F
T
What structures in the adult does the metanephros give rise to
The metanephros gives rise to the kidney proper
What type of cells are contained in the intermediate mesoderm
Mesenchymal cells
What is the result of a conditional knockout/loss of six2 expression
Depletion of the nephron stem cell pool
Discuss the ultimate fate of the mesonephros
The mesonephros largely generates, However, in males, some tubules retained and form vas deferens. But by now, the metanephric (definitive) kidney has been induced
Which structure expresses wt1 involved in kidney development
Nephric cord
Kidney development is protracted, proceeding throughout prenatal and even into postnatal life, T or F
T
