Factores que determinan la asimetría en las primeras divisiones celulares del embrión

Abstract

During the early stages of embryonic development, asymmetric cell divisions are crucial for

differentiation into the cellular lineages of trophectoderm (TE) and inner cell mass (ICM).

The main objective of this present work was to identify the molecules that influence the

asymmetry of these divisions towards one of the two cellular linages during

preimplantational embryo development in mammals. To this end, a review of the most recent

literature on this topic was carried out. The analyzed articles were grouped according to the

type of molecule studied: lncRNA (Long Non-Coding RNA), transcription factors, metabolism

and metabolites, cytoskeleton, and other proteins. Most studies used the mice as their

animal model, although it is worth highlighting that some studies used the pig. It was

identified that some lncRNAs, such as LincGET, regulate gene expression associated with

differentiation in the ICM. Transcription factors such as Cdx2, Oct4, Sox2, or TEAD4, and

signaling pathways like Hippo and Notch, play a key role in cell specification towards one of

the cellular lineages. At a metabolic level, it was observed that the differential use of glucose,

pyruvate, and lipids regulates essential cellular processes such as pluripotency, polarization,

and cell cycle progression. Regarding the cytoskeleton, the role of proteins such as JMY

and RhoA stands out in the organization of actin filaments and cell polarity, as well as the

influence of the pressure of the blastocyst lumen on cell fate. Finally, other proteins such as

ZP3, DDX1, and ACTB were identified to affect the asymmetric distribution of cellular

components and the activation of the embryonic genome. Altogether, this review highlights

the diversity of molecular mechanisms involved in asymmetric embryonic divisions and their

relevance to early embryonic development

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