a:4:{s:10:"Background";s:1707:"Early embryonic development in mammals begins in transcriptional silence with an oocyte-mediated transcriptional reprogramming of parental gametes occurs during a so called across-the-board process of “erase-and-rebuild”. In this process, the parental transcription programs are erased long before (maternal) or soon thereafter (paternal) fertilization to generate a...

Studies on cell fusion-mediated nuclear reprogramming have led to the breakthrough of the induced pluripotent stem (iPS) cell technology. While this technology has neared stem cells to applications more than any other method, the mechanistic bases of reprogramming remain largely unsolved. In this context, comparative studies of oocyte and cell fusion-mediated reprogramming hold the greatest pro...

s:1202:"It is a truly amazing time to developmental biology. During recent decades, three important breakthroughs have been developed: (i) isolation of stem cells from embryo, (ii) animal cloning by nuclear transfer (NT), and (iii) and induced pluripotent stem cells (iPS). Considering these three approaches of "Cellular Reprogramming", it seems that the required elements for cell therapy now ex...

Many of the structural and mechanistic requirements of oocyte-mediated nuclear reprogramming remain elusive. Previous accounts that transcriptional reprogramming of somatic nuclei in mouse zygotes may be complete in 24-36 hours, far more rapidly than in other reprogramming systems, raise the question of whether the mere exposure to the activated mouse ooplasm is sufficient to enact reprogrammin...

Background: The mammalian oocyte has the unique feature of supporting fertilization and normal development while being able of reprogramming the nuclei of somatic cells towards pluripotency, and occasionally even totipotency. Whilst oocyte quality is known to decay with somatic ageing, it is not a given that different biological functions decay concurrently. In this study, we tested whether ooc...

Nuclear transfer to oocytes is an efficient way to transcriptionally reprogram somatic nuclei, but its mechanisms remain unclear. Here, we identify a sequence of molecular events that leads to rapid transcriptional reprogramming of somatic nuclei after transplantation to Xenopus oocytes. RNA-seq analyses reveal that reprogramming by oocytes results in a selective switch in transcription toward ...

DNA demethylation, a process involving DNA repair, is critical for reprogramming of the paternal genome during the oocyte-to-zygote transition. A new study by Ladstätter and Tachibana-Konwalski shows that a Chk1-mediated zygotic checkpoint monitors the cohesin-dependent repair of DNA lesions arising from DNA demethylation, which prevents zygotes carrying unrepaired lesions from entering mitosis.

The ability to reprogram in vivo a somatic cell after differentiation is quite limited. One of the most impressive examples of such a process is transdifferentiation of pigmented epithelial cells (PECs) to lens cells during lens regeneration in newts. However, very little is known of the molecular events that allow newt cells to transdifferentiate. Histone B4 is an oocyte-type linker histone th...

Nuclear reprogramming of differentiated cells can be induced by oocyte factors. Despite numerous attempts, these factors and mechanisms responsible for successful reprogramming remain elusive. Here, we identify one such factor, necessary for the development of nuclear transfer embryos, using porcine oocyte extracts in which some reprogramming events are recapitulated. After incubating somatic n...

The oocyte is the only cell of the body that can reprogram transplanted somatic nuclei and sets the gold standard for all reprogramming methods. Therefore, an in-depth characterization of its proteome holds promise to advance our understanding of reprogramming and germ cell biology. To date, limitations on oocyte numbers and proteomic technology have impeded this task, and the search for reprog...