ABSTRACT

The Hnf1b-CreER^T2 BAC transgenic (Tg(Hnf1b-cre/ERT2)1Jfer) has been used extensively to trace the progeny of pancreatic ducts in developmental, regeneration, or cancer models. Hnf1b-CreER^T2 transgenics have been used to show that the cells that form the embryonic pancreas duct-like plexus are bipotent duct-endocrine progenitors, whereas adult mouse duct cells are not a common source of β cells in various regenerative settings. The interpretation of such genetic lineage tracing studies is critically dependent on a correct understanding of the cell type specificity of recombinase activity with each reporter system. We have reexamined the performance of Hnf1b-CreER^T2 with a Rosa26-RFP reporter transgene. This showed inducible recombination of up to 96% adult duct cells, a much higher efficiency than previously used reporter transgenes. Despite this high duct-cell excision, recombination in α and β cells remained very low, similar to previously used reporters. However, nearly half of somatostatin-expressing δ cells showed reporter activation, which was due to Cre expression in δ cells rather than to duct to δ cell conversions. The high recombination efficiency in duct cells indicates that the Hnf1b-CreER^T2 model can be useful for both ductal fate mapping and genetic inactivation studies. The recombination in δ cells does not modify the interpretation of studies that failed to show duct conversions to other cell types, but needs to be considered if this model is used in studies that aim to modify the plasticity of pancreatic duct cells.

摘要

Hnf1b -CreER ^T2 BAC 转基因 (Tg( Hnf1b -cre/ERT2)1Jfer) 已被广泛用于追踪发育、再生或癌症模型中胰管的后代。Hnf1b -CreER ^T2转基因已被用于表明形成胚胎胰腺导管样丛的细胞是双能导管内分泌祖细胞，而成年小鼠导管细胞在各种再生环境中不是 β 细胞的常见来源。对此类遗传谱系追踪研究的解释主要取决于对每个报告系统的重组酶活性的细胞类型特异性的正确理解。我们重新检查了Hnf1b -CreER ^T2的性能带有 Rosa26-RFP 报告基因转基因。这显示了高达 96% 的成年导管细胞的可诱导重组，比以前使用的报告转基因效率高得多。尽管进行了这种高导管细胞切除，但 α 和 β 细胞中的重组仍然非常低，类似于以前使用的报告基因。然而，近一半的表达生长抑素的 δ 细胞显示报告基因激活，这是由于 Cre 在 δ 细胞中的表达，而不是导管向 δ 细胞的转化。导管细胞中的高重组效率表明Hnf1b -CreER ^T2模型可用于导管命运图和遗传失活研究。δ 细胞中的重组不会改变对未能显示导管转化为其他细胞类型的研究的解释，但如果该模型用于旨在改变胰管细胞可塑性的研究，则需要考虑。