IISER MOHALI

Abstract: Coordination of cell behaviors is essential for growth in embryonic and juvenile animals, as well as during regeneration of tissue lost by damage or disease. This is particularly challenging for stratified tissues, such as skin, during rapid phases of growth in embryonic development and adult regeneration. Here, multiple cell layers would have to communicate effectively and growtogether to ensure stratification remains unaffected. How skin cell layers behave and coordinate their growth when challenged with rapid expansion requires research attention but has been limited by the availability of tools and platforms for quantitative live imaging. Using zebrafish periderm, the outermost layer of the bilayer epidermis, we aim to understand how epidermis behaves and coordinates its growth when challenged with rapid embryonic axial expansion.\nHere, we developed platform to perform high cellular resolution in toto live imaging and atoolkit to quantitatively elucidate these processes. Employing this toolkit, we find that peridermelongation is facilitated by oriented cell divisions, rather than cell addition from basal layer.Using transgenic lines expressing an ERK biosensor and optogenetic perturbations, we find thatERK activity is necessary and sufficient for proliferation. The rate of proliferation and elongationboth decrease over time, as ERK activity transitions to a more pulsatile pattern. By imaging ERKand Cdk activity simultaneously using biosensors, we find that cells transition from aproliferative to a non-proliferative response to ERK signaling as development progresses.Remarkably, we discover that cells employ the same signaling pathway but modulate theirresponse depending on developmental timing.\nUsing this established toolkit, in my lab I aim to generate a blueprint of cell behaviors andsignaling in the embryonic and adult epidermis and determine features that are conservedacross tissues during adult regeneration upon injury. This comprehensive analysis of cellbehaviors and signaling in the epidermis will inform strategies for control of repair in humanconditions of tissue damage or disease.\n\nMeeting ID: 987 9698 1237\nPasscode: 714133\n