Skip to content
Login Register

#germline

2 public questions tagged with this topic.

C-Elegans Development-l

Which protein prevents somatic differentiation in germline cells?

PIE-1 contains tandem CCCH zinc fingers highly enriched in P lineage P2-P4 and germline precursors associated with P-granules. It binds and inhibits P-TEFb cyclin T CDK-9 transcription elongation factor, blocking Ser2 phosphorylation of RNA polymerase II carboxy-terminal domain globally repressing mRNA synthesis. This prevents activation of somatic genes hlh-1 muscle, pha-4 pharynx, elt-2 intestine normally induced by SKN-1 and PAL-1. PIE-1 colocalizes with P-granules protecting germline genome via small RNA pathways including PRG-1. Mutants lacking PIE-1 show P2 transforming into EMS-like cells producing gut at expense of germline.

Ref: Mello et al., Science 1996: PIE-1 zinc-finger protein prevents somatic differentiation in germline by repressing transcription.

View Details
C-Elegans Development-l

Which blastomere gives rise to the germline in C. elegans?

Germline derives exclusively from continuous P lineage through sequential asymmetric divisions preserving totipotency. P0 divides into AB and P1, P1 into EMS and P2, P2 into C and P3, P3 into D and P4. P4, the smallest blastomere at 24-cell stage, divides symmetrically into Z2 and Z3 primordial germ cells quiescent until larval feeding. P-granules, maternally deposited ribonucleoprotein complexes containing GLH helicases and PGL scaffold, segregate into P cells, repress somatic transcription via PIE-1 inhibition of P-TEFb, maintaining germ potential throughout embryogenesis.

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 8: Germline specification - P lineage and P-granule segregation in C. elegans.

View Details