B cells migrate to the lymphoid follicles. They are directed there by chemokine interactions between CXCL13, which is secreted by follicular dendritic cells (FDCs).

TLS Online TPP Program

#Id: 7431

#Unit 5. Developmental Biology

CMF stimulates gene expression in parallel with PSF, and both signals potentiate cAMP signalling by inducing genes involved in cAMP synthesis and detection

TLS Online TPP Program

#Id: 7432

#Unit 5. Developmental Biology

Newly activated genes are:

Adenylate cyclase A (ACA)

PKA

cAMP receptors (cARs)

Extracellular cAMP phosphodiesterase PdsA

An intracellular cAMP phosphodiesterase RegA

TLS Online TPP Program

#Id: 7433

#Unit 5. Developmental Biology

Once all proteins are functioning, a few starving cells start to emit cAMP pulses.

TLS Online TPP Program

#Id: 7434

#Unit 5. Developmental Biology

Chemotaxis of Dictyostelium myxamoebae is a result of spiral waves of cAMP.

TLS Online TPP Program

#Id: 7435

#Unit 5. Developmental Biology

Neighboring cells respond to cAMP in two ways:

Initiate a movement toward the cAMP pulse for about a minute

Release cAMP of their own

TLS Online TPP Program

#Id: 7436

#Unit 5. Developmental Biology

The top of the mound continues to emit cAMP pulses and is pushed upwards by the movement of cells underneath