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The origin of betaine in mouse oocytes and preimplantation embryos†.
McIntosh, Emily R; McClatchie, Taylor; Lee, Martin; Zeisel, Steven H; Jurisicova, Andrea; Baltz, Jay M.
Afiliação
  • McIntosh ER; Ottawa Hospital Research Institute, Ottawa, ON, Canada.
  • McClatchie T; Department of Cellular and Molecular Medicine, University of Ottawa Faculty of Medicine, Ottawa, ON, Canada.
  • Lee M; Ottawa Hospital Research Institute, Ottawa, ON, Canada.
  • Zeisel SH; Ottawa Hospital Research Institute, Ottawa, ON, Canada.
  • Jurisicova A; Biotechnology Program, Algonquin College, Ottawa, ON, Canada.
  • Baltz JM; Department of Nutrition, Nutrition Research Institute, Gillings School of Global Public Health and School of Medicine, University of North Carolina, Chapel Hill, NC, USA.
Biol Reprod ; 111(1): 63-75, 2024 Jul 12.
Article em En | MEDLINE | ID: mdl-38702845
ABSTRACT
Betaine has important roles in preimplantation mouse embryos, including as an organic osmolyte that functions in cell volume regulation in the early preimplantation stages and as a donor to the methyl pool in blastocysts. The origin of betaine in oocytes and embryos was largely unknown. Here, we found that betaine was present from the earliest stage of growing oocytes. Neither growing oocytes nor early preantral follicles could take up betaine, but antral follicles were able to transport betaine and supply the enclosed oocyte. Betaine is synthesized by choline dehydrogenase, and female mice lacking Chdh did not have detectable betaine in their oocytes or early embryos. Supplementing betaine in their drinking water restored betaine in the oocyte only when supplied during the final stages of antral follicle development but not earlier in folliculogenesis. Together with the transport results, this implies that betaine can only be exogenously supplied during the final stages of oocyte growth. Previous work showed that the amount of betaine in the oocyte increases sharply during meiotic maturation due to upregulated activity of choline dehydrogenase within the oocyte. This betaine present in mature eggs was retained after fertilization until the morula stage. There was no apparent role for betaine uptake via the SIT1 (SLC6A20) betaine transporter that is active at the 1- and 2-cell stages. Instead, betaine was apparently retained because its major route of efflux, the volume-sensitive organic osmolyte - anion channel, remained inactive, even though it is expressed and capable of being activated by a cell volume increase.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Oócitos / Betaína / Blastocisto Limite: Animals Idioma: En Revista: Biol Reprod Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Canadá

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Oócitos / Betaína / Blastocisto Limite: Animals Idioma: En Revista: Biol Reprod Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Canadá