Differential Expression of 26S Proteasome Subunits and Functional Activity during Neonatal Development
Bibliographic record
Abstract
Proteasomes regulate many essential cellular processes by degrading intracellular proteins. While aging is known to be associated with dysfunction of the proteasome, there are few reports detailing activity and function of proteasomes in the early stages of life. To elucidate the function and development of mammalian proteasomes, 26S proteasomes were affinity-purified from rat intestine, spleen and liver. The developmental expression of core, regulatory and immunoproteasome subunits was analyzed by immunoblotting and reverse-transcriptase PCR of mRNA subunits, and proteasome catalytic function was determined by fluorogenic enzymatic assays. The expression of core (β2, β5, α7 and β1) and regulatory (Rpt5) subunits was found to be present at low levels at birth and increased over time particularly at weaning. In contrast, while gradual developmental progression of proteasome structure was also seen with the immunoproteasome subunits (β1i, β5i, and β2i), these were not present at birth. Our studies demonstrate a developmental pattern to 26S proteasome activity and subunit expression, with low levels of core proteasome components and absence of immunoproteasomes at birth followed by increases at later developmental stages. This correlates with findings from other studies of a developmental hyporesponsiveness of the adaptive immune system to allow establishment of microbial colonization immediately after birth.
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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 | 0.001 |
| 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) | 0.001 | 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 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".