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PR-B

Meaning

PR-B, or Progesterone Receptor-B, is the full-length isoform of the human progesterone receptor, a critical nuclear receptor protein that mediates the genomic actions of the steroid hormone progesterone. PR-B contains a unique N-terminal sequence that includes a potent third transcriptional activation domain, which is absent in the shorter PR-A isoform. This structural feature renders PR-B a much stronger transcriptional activator, driving the full spectrum of progesterone’s effects in target tissues.