174 Defining the composition and function of Lamin ribonuclear bodies during keratinocyte terminal differentiation and nuclear degradation

Keratinocyte cornification and epidermal barrier formation are tightly controlled processes, requiring degradation of organelles, including the nucleus. However, underlying molecular mechanisms not well defined. We have identified myosin II-mediated dispersal an internal fragment Lamin A (LMNA) during end-stage terminal differentiation prior to nuclear degradation. non-membrane-bound LMNA bodies were distinct from keratohyalin granules lamellar associated both with RNA components envelope. therefore wished determine composition function these lamin ribonuclear (LRBs). used single cell sequencing probe dynamics mRNA transcription late differentiation, pulldowns constructs followed by proteomics ascertain protein LRBs. widespread up-regulation ribosomal mRNAs, that correlated preferential pull down proteins central LMNA, as translation machinery, pore. Taken together this suggested areas active synthesis in cells undergoing Consistent our previous findings, we found Myosin II also LRBs confirming association Therefore, a new structure terminally differentiating epidermis could be maintained keratinocyte destruction