Connexin43 is not expressed in principal cells of mouse cortex and hippocampus
Bibliographic record
Abstract
Previous immunofluorescence analyses in mice and rats showed a mainly astrocytic expression of the gap junction protein connexin43 (Cx43) in brain. However, in situ hybridization of murine brain sections suggested strong expression of Cx43 mRNA in hippocampal and cortical pyramidal neurons and Purkinje cells. These findings contrast with recent immunoelectron microscopic studies that excluded prominent Cx43 protein expression in neurons. Both contrasting results could be explained by post-transcriptional control mechanisms. Here we demonstrate by conditional replacement of the Cx43 coding region by a lacZ reporter gene, mimicking transcriptional activity of the Cx43 gene, that Cx43 is not expressed in principal cells of murine brain. This histochemical approach used is not prone to cross-reactivity of mRNA probes or antibodies. Furthermore, we show that in situ hybridization signals, suggested to be specific for Cx43 in mouse neurons, are retained even when the Cx43 coding DNA in neurons is removed by cre-mediated deletion. Our results confirm the previous findings of a mainly astrocytic expression of Cx43 in adult mouse brain and underscore the importance of connexin-deficient mice as controls for in situ hybridization studies. We found no evidence for post-transcriptional control of the Cx43 gene in principal neurons. Thus, the synchronized activity of neuronal networks cannot depend on Cx43 containing gap junctions in these cells.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".