Bio 132 Lecture 11 Intermediate Mesoderm 2024 PDF

INTERMEDIATE MESODERM G i l b e r t a n d B a r r e s i , 1 1 th e d p p 5 8 5 - 5 9 0 PARTITIONS AND LINEAGES OF THE MESODERM PARTITIONS AND LINEAGES OF THE MESODERM KIDNEY AND NEPHRON INTERMEDIATE MESODERM: KIDNEY INTERMEDIATE MESODERM: KIDNEY EARLY SPECIFICATION When paraxial m...

INTERMEDIATE MESODERM G i l b e r t a n d B a r r e s i , 1 1 th e d p p 5 8 5 - 5 9 0 PARTITIONS AND LINEAGES OF THE MESODERM PARTITIONS AND LINEAGES OF THE MESODERM KIDNEY AND NEPHRON INTERMEDIATE MESODERM: KIDNEY INTERMEDIATE MESODERM: KIDNEY EARLY SPECIFICATION When paraxial mesoderm is detached from intermediate mesoderm, no kidneys are formed. Lim1 , Pax2, and Pax8 are NOT expressed in the intermediate mesoderm, no kidneys are formed. When the intermediate mesoderm is not competent to respond to activin, no kidneys are formed. RECIPROCAL INTERACTIONS OF DEVELOPING KIDNEY TISSUES  RECIPROCAL INDUCTION : Metanephric mesenchyme (MM) Ureteric bud (UB) STEP 1: Migrated late, long Wnt exposure, then Fgf9 and RA Migrated early, short Wnt exposure, FORMATION OF long Fgf9 and RA exposure MM AND UB STEP 2: MM MM secretes GDNF INDUCE UB Nephric duct with Ret emerge into UB (RA from surrounding tissues)  Metanephric mesenchyme (MM) Ureteric bud (UB) STEP 3: UB Secretes Fgf2,9 and Bmp7 (Fgfs,Bmps) to MM inhibits apoptosis MM survive (no apoptosis) and proliferate, condense, and maintain WT1 STEP 4: MM to UB MM continuous GDNF induce branching Wnt 11 synthesis GDNF maintained Stem cell Maintained Mesenchyme cap cells Ureteric bud tip cells STEP 5: UB to MM Wnt6 and 9 release Tubules/nephron Wnt4 express , acts on MM to form epi cells for nephron FATES OF DIFFERENT KIDNEYS AND THEIR DUCTS WITH FURTHER DEVELOPMENT Dependent on the species Closely associated with the development of the gonads and the posterior end of the gut – Mesonephros degenerates, some tubules are incorporated into male gonad – Mesonephric ducts used as duct of male gonad but degenerates in female – In humans metanephros “ascends” Development of the kidney, gonads and reproductive tubes Adolescent Medicine, 2008 http://www.dhushara.com/paradoxhtm/biology/gonads2.jpg A. EXPLAIN THE MORPHOGENESIS OF KIDNEY IN 5 STEPS  B. EXPLAIN THE MOLECULAR RECIPROCAL INDUCTION BETWEEN THE MM AND UB Be creative as possible Be sure to incorporate the following signaling molecules – Fgf9 and RA/Wnt – GDNF/Ret – Fgf2,9 and Bmp7 – WT1 – GDNF,/Wnt11 – Wnt6,9,4 PARTITIONS AND LINEAGES OF THE MESODERM