Expression of Calbindin-D28k (CaBP28k) in Trophoblasts from Human Term Placenta1
Bibliographic record
Abstract
Calbindin-D28k (CaBP28k) belongs to a large class of eucaryotic proteins that bind calcium (Ca2+) to a specific helix-loop-helix structure. To date, this protein was mainly linked to brain, kidneys, and pancreas. Here, we demonstrate for the first time the existence of CaBP8k in the human placental trophoblasts of the human term placenta. Placental Ca2+ transfer from maternal to fetus is crucial for fetal development, although the biochemical mechanisms responsible for this process are largely unknown. In the current study, we have investigated the 45Ca2+ uptake by human trophoblast cells in correlation with the expression CaBP28k. The expression of CaBP28k was determined by Northern blot analysis, reverse transcriptase polymerase chain reaction (RT-PCR), immunochemistry, and Western blot analysis. Indeed, Northern blot analysis revealed the presence of a CaBP28k transcript in syncytiotrophoblasts, cytotrophoblast cells, and HEK-293 cells. This was further confirmed by RT-PCR analysis followed by sequencing. In addition, anti-CaBP28k labeling was associated with cytotrophoblast and syncytiotrophoblast tissues in placental tissue sections and in vitro cultured cells. The presence of CaBP28k protein in these cells was confirmed by Western blotting. Cytotrophoblast cells isolated from human term placenta showed differentiation into syncytiotrophoblasts in culture according to the increase in hCG secretion. Both Ca2+ uptake and hCG secretion by trophoblasts increased gradually and were high at Day 4. Taken together, these data suggest that CaBP28k may play a role in Ca2+ transport or cell development in human trophoblast possibly trough Ca2+ buffering.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".