Efficient allele conversion in mouse zygotes and primary cells based on electroporation of Cre protein

It has been proposed that gonadotropin-releasing hormone (GnRH) stimulates Ca2+ entry by activation of voltage-independent, receptor-mediated Ca2+ channels in the rat gonadotroph. Little work has been done on the role of calcium in GnRH-induced luteinizing hormone (LH) release in species other than the rat. Therefore, this study was done to compare the effects of agents that alter Ca2+ or Na+ entry on LH release from calf anterior pituitary primary cells in culture. GnRH (100 ng/ml), Ca2+ ionophore A23187 (2.5 microM), and the depolarizing agent ouabain (0.1-10 microM) all produced significant increases (P less than 0.05) in LH release; these effects were significantly reduced when the cells were preincubated with the organic Ca2+ channel blockers nifedipine (1-10 microM) and verapamil (1-10 microM) and with Co2+ (0.01-1 mM). The effect of ouabain was inhibited by tetrodotoxin (TTX; 1-10 nM) as well as by nifedipine at 0.1-10 microM. In contrast to its effect on rat pituitary LH release, TTX significantly inhibited GnRH-stimulated LH release at 1-100 nM. These results suggest that GnRH-induced LH release may employ Ca2+ as a second messenger in bovine gonadotrophs and support recent speculation that GnRH-induced Ca2+ mobilization may in part be voltage dependent.

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Totipotency of mouse zygotes extends to single blastomeres of embryos at the four-cell stage

Scientific Reports ◽

10.1038/s41598-021-90653-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Marino Maemura ◽

Hiroaki Taketsuru ◽

Yuki Nakajima ◽

Ruiqi Shao ◽

Ayaka Kakihara ◽

...

Keyword(s):

Inner Cell Mass ◽

Cell Mass ◽

Mouse Embryos ◽

Primitive Endoderm ◽

Cell Stage ◽

Supportive Environment ◽

Mouse Zygotes ◽

Single Blastomeres ◽

Multicellular Organisms

AbstractIn multicellular organisms, oocytes and sperm undergo fusion during fertilization and the resulting zygote gives rise to a new individual. The ability of zygotes to produce a fully formed individual from a single cell when placed in a supportive environment is known as totipotency. Given that totipotent cells are the source of all multicellular organisms, a better understanding of totipotency may have a wide-ranging impact on biology. The precise delineation of totipotent cells in mammals has remained elusive, however, although zygotes and single blastomeres of embryos at the two-cell stage have been thought to be the only totipotent cells in mice. We now show that a single blastomere of two- or four-cell mouse embryos can give rise to a fertile adult when placed in a uterus, even though blastomere isolation disturbs the transcriptome of derived embryos. Single blastomeres isolated from embryos at the eight-cell or morula stages and cultured in vitro manifested pronounced defects in the formation of epiblast and primitive endoderm by the inner cell mass and in the development of blastocysts, respectively. Our results thus indicate that totipotency of mouse zygotes extends to single blastomeres of embryos at the four-cell stage.

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Gender-Dependent Phenotype in Polycystic Kidney Disease Is Determined by Differential Intracellular Ca2+ Signals

International Journal of Molecular Sciences ◽

10.3390/ijms22116019 ◽

2021 ◽

Vol 22 (11) ◽

pp. 6019

Author(s):

Khaoula Talbi ◽

Inês Cabrita ◽

Rainer Schreiber ◽

Karl Kunzelmann

Keyword(s):

Cell Proliferation ◽

Kidney Disease ◽

Polycystic Kidney Disease ◽

Collecting Duct ◽

Primary Cells ◽

Loss Of Function ◽

Polycystic Kidney ◽

Chloride Currents ◽

Duct Cells ◽

Collecting Duct Cells

Autosomal dominant polycystic kidney disease (ADPKD) is caused by loss of function of PKD1 (polycystin 1) or PKD2 (polycystin 2). The Ca2+-activated Cl− channel TMEM16A has a central role in ADPKD. Expression and function of TMEM16A is upregulated in ADPKD which causes enhanced intracellular Ca2+ signaling, cell proliferation, and ion secretion. We analyzed kidneys from Pkd1 knockout mice and found a more pronounced phenotype in males compared to females, despite similar levels of expression for renal tubular TMEM16A. Cell proliferation, which is known to be enhanced with loss of Pkd1−/−, was larger in male when compared to female Pkd1−/− cells. This was paralleled by higher basal intracellular Ca2+ concentrations in primary renal epithelial cells isolated from Pkd1−/− males. The results suggest enhanced intracellular Ca2+ levels contributing to augmented cell proliferation and cyst development in male kidneys. Enhanced resting Ca2+ also caused larger basal chloride currents in male primary cells, as detected in patch clamp recordings. Incubation of mouse primary cells, mCCDcl1 collecting duct cells or M1 collecting duct cells with dihydrotestosterone (DHT) enhanced basal Ca2+ levels and increased basal and ATP-stimulated TMEM16A chloride currents. Taken together, the more severe cystic phenotype in males is likely to be caused by enhanced cell proliferation, possibly due to enhanced basal and ATP-induced intracellular Ca2+ levels, leading to enhanced TMEM16A currents. Augmented Ca2+ signaling is possibly due to enhanced expression of Ca2+ transporting/regulating proteins.

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Cyclopenta[b]indole Derivative Inhibits Aurora B in Primary Cells

ACS Omega ◽

10.1021/acsomega.0c05491 ◽

2020 ◽

Vol 5 (51) ◽

pp. 33455-33460

Author(s):

Andreas Ekebergh ◽

Jerker Mårtensson ◽

Christine Lingblom Ekebergh

Keyword(s):

Indole Derivative ◽

Aurora B ◽

Primary Cells

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STAT3 Is an Upstream Regulator of Granzyme G in the Maternal-To-Zygotic Transition of Mouse Embryos

International Journal of Molecular Sciences ◽

10.3390/ijms22010460 ◽

2021 ◽

Vol 22 (1) ◽

pp. 460

Author(s):

Huan Ou-Yang ◽

Shinn-Chih Wu ◽

Li-Ying Sung ◽

Shiao-Hsuan Yang ◽

Shang-Hsun Yang ◽

...

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Fluorescent Protein ◽

Mouse Embryos ◽

Cell Nuclei ◽

Cell Stage ◽

Promoter Assay ◽

Maternal To Zygotic Transition ◽

Mouse Zygotes ◽

Time Specific

The maternal-to-zygotic transition (MZT), which controls maternal signaling to synthesize zygotic gene products, promotes the preimplantation development of mouse zygotes to the two-cell stage. Our previous study reported that mouse granzyme g (Gzmg), a serine-type protease, is required for the MZT. In this study, we further identified the maternal factors that regulate the Gzmg promoter activity in the zygote to the two-cell stage of mouse embryos. A full-length Gzmg promoter from mouse genomic DNA, FL-pGzmg (−1696~+28 nt), was cloned, and four deletion constructs of this Gzmg promoter, Δ1-pGzmg (−1369~+28 nt), Δ2-pGzmg (−939~+28 nt), Δ3-pGzmg (−711~+28 nt) and Δ4-pGzmg (−417~+28 nt), were subsequently generated. Different-sized Gzmg promoters were used to perform promoter assays of mouse zygotes and two-cell stage embryos. The results showed that Δ4-pGzmg promoted the highest expression level of the enhanced green fluorescent protein (EGFP) reporter in the zygotes and two-cell embryos. The data suggested that time-specific transcription factors upregulated Gzmg by binding cis-elements in the −417~+28-nt Gzmg promoter region. According to the results of the promoter assay, the transcription factor binding sites were predicted and analyzed with the JASPAR database, and two transcription factors, signal transducer and activator of transcription 3 (STAT3) and GA-binding protein alpha (GABPα), were identified. Furthermore, STAT3 and GABPα are expressed and located in zygote pronuclei and two-cell nuclei were confirmed by immunofluorescence staining; however, only STAT3 was recruited to the mouse zygote pronuclei and two-cell nuclei injected with the Δ4-pGzmg reporter construct. These data indicated that STAT3 is a maternal transcription factor and may upregulate Gzmg to promote the MZT. Furthermore, treatment with a STAT3 inhibitor, S3I-201, caused mouse embryonic arrest at the zygote and two-cell stages. These results suggest that STAT3, a maternal protein, is a critical transcription factor and regulates Gzmg transcription activity in preimplantation mouse embryos. It plays an important role in the maternal-to-zygotic transition during early embryonic development.

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