Biomedical subjects

Karin Hübner

Publications and source records attributed to Karin Hübner.

4 recordsLinked to original sources

PubMed2006

Oocytes.

Embryonic stem cells (ESCs), derivatives of totipotential cells of early mammalian embryos, have proven to be one of the most powerful tools for studying developmental and stem cell biology. When injected into embryos, ESCs can contribute to tissues derived from all three germ layers and to the germ line. Prior studies have successfully shown that ESCs can recapitulate features of embryonic development by spontaneously forming somatic lineages in culture. More recent studies using differentiating monolayer cultures and embryoid bodies have shown that mouse ESCs can also form germ cells that are capable of undergoing meiosis and forming both male and female gametes. This chapter provides detailed instruction on how to differentiate ESCs in monolayer cultures to derive germ cells and oocyte-like structures and presents standard methodologies for detecting expression of key genetic pathways required for primordial germ cell (PGC) development and oogenesis in vivo. While the full potential of these ESC-derived germ cells and oocyte-like structures remains to be demonstrated, this assay provides a new approach to studying reproductive developmental biology in vitro.

Animals↗

PubMed2006

Spermatogonia: origin, physiology and prospects for conservation and manipulation of the male germ line.

In recent years, the scientific community has become increasingly interested in spermatogonia. Methodological breakthroughs, such as germ cell transplantation and spermatogonial culture combined with novel germ line transfection strategies, have provided interesting new opportunities for studying the physiology of spermatogonial stem cells and their interaction with the stem cell niche. Furthermore, intense research into pluripotent and adult stem cells has generated new insight into the differentiation pathway of germ line stem cells and has opened new perspectives for stem cell technologies. The present review briefly introduces the physiology of spermatogonial stem cells and discusses future directions of basic research and practical approaches applicable to livestock maintenance and animal reproduction.

Animals↗

PubMed2003

Derivation of oocytes from mouse embryonic stem cells.

Continuation of mammalian species requires the formation and development of the sexually dimorphic germ cells. Cultured embryonic stem cells are generally considered pluripotent rather than totipotent because of the failure to detect germline cells under differentiating conditions. Here we show that mouse embryonic stem cells in culture can develop into oogonia that enter meiosis, recruit adjacent cells to form follicle-like structures, and later develop into blastocysts. Oogenesis in culture should contribute to various areas, including nuclear transfer and manipulation of the germ line, and advance studies on fertility treatment and germ and somatic cell interaction and differentiation.

Animals↗

PubMed2002

Allele-specific expression of imprinted genes in mouse migratory primordial germ cells.

In somatic cells, imprinted genes are expressed monoallelically according to parent-of-origin. In contrast, in 11.5 days post-coitum primordial germ cells (PGCs), and later stage germ cells, these same genes are expressed biallelically, suggesting that imprints inherited from the gametes are largely erased by this stage. To determine when in germ cell development this biallelic expression phenomenon commences, we isolated migrating PGCs by flow cytometry and determined the allele-specific expression of four imprinted genes - Snrpn, Igf2, H19 and Igf2r. The first three genes were expressed monoallelically, while the latter gene was expressed biallelically. These results show that inherited imprints regulating monoallelic expression are largely intact in migrating PGCs.

Alleles↗