A critical developmental role for tgfbr2 in myogenic cell lineages is revealed in mice expressing SM22-Cre, not SMMHC-Cre
A critical developmental role for tgfbr2 in myogenic cell lineages is revealed in mice expressing SM22-Cre, not SMMHC-Cre
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DOI：
10.1016/j.yjmcc.2006.06.067
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发表时间：
2006-10-01
影响因子：
5
通讯作者：
Dichek, David A.
中科院分区：
文献类型：
--
作者：
Frutkin, Andrew D.;Shi, Haikun;Dichek, David A.
平滑肌细胞（SMC）特异性缺失转化生长因子β（TGF-β）信号传导将有助于阐明TGF-β信号传导促进血管发育和疾病的机制。我们试图通过将具有11型TGF-β受体（tgfbr 2（flox））的条件性（“floxed”）等位基因的小鼠与具有SMC靶向表达Cre重组酶的小鼠交配来产生具有SMC特异性TGF-β信号传导缺失的小鼠。我们培育了平滑肌肌球蛋白重链（SMMHC）-Cre转基因雄性小鼠与携带tgfbr 2（flox）的雌性小鼠。令人惊讶的是，SMMHC-Cre rnice在SMC中以低水平重组tglbr 2（flox），在睾丸中以高水平重组tglbr 2。tgfbr 2（flox）在睾丸中的表达与SMMHC-Cre在睾丸中的高水平表达和tgfbr 2（null）的胚系传递相关。相比之下，从SM 22 α启动子（SM 22-Cre）表达Cre的小鼠在血管和内脏SMC和心脏中有效地重组了tgfbr 2（flox），但在睾丸中没有。使用R26 R报告等位基因证实了Cre介导的血管SMC重组对于SMMHC-Cre小鼠是低效的，而对于SM 22-Cre小鼠是高效的。将SM 22-Cre等位基因引入tgfbr 2（flox）合子中以产生成年小鼠，所述成年小鼠对于SM 22-Cre是半合子的并且对于tgfbr 2（flox）是纯合子的，并且在SMC产生的无活SM 22-Cre：tgfbr 2（flox/flox）幼崽中将具有tgfbr 2（flox/flox）向tgfbr 2（null/null）的转化（P < 0.001）。我们得出结论：（1）“SMC靶向”Cre系在Cre表达的特异性和效率方面显著不同;（2）表达SM 22 α的细胞亚群中的TGF-β信号传导是正常发育所需的;（3）SMC中缺乏TGF-β信号传导的成年小鼠的产生仍然是一个挑战。(c)2006年爱思唯尔公司All rights reserved.
Smooth muscle cell (SMC)-specific deletion of transforming growth factor beta (TGF-beta) signaling would help elucidate the mechanisms through which TGF-beta signaling contributes to vascular development and disease. We attempted to generate mice with SMC-specific deletion of TGF-beta signaling by mating mice with a conditional ("floxed") allele for the type 11 TGF-beta receptor (tgfbr2(flox)) to mice with SMC-targeted expression of Cre recombinase. We bred male mice transgenic for smooth muscle myosin heavy chain (SMMHC)-Cre with females carrying tgfbr2(flox). Surprisingly, SMMHC-Cre rnice recombined tglbr2(flox) at low levels in SMC and at high levels in the testis. Recombination of tgfbr2(flox) in testis correlated with high-level expression of SMMHC-Cre in testis and germline transmission of tgfbr2(null). In contrast, mice expressing Cre from a SM22 alpha promoter (SM22-Cre) efficiently recombined tgfbr2(flox) in vascular and visceral SMC and the heart, but not in testis. Use of the R26R reporter allele confirmed that Cre-mediated recombination in vascular SMC was inefficient for SMMHC-Cre mice and highly efficient for SM22-Cre mice. Breedings that introduced the SM22-Cre allele into tgfbr2(flox) zygotes in order to generate adult mice that are hemizygous for SM22-Cre and homozygous for tgfbr2(flox) and would have conversion of tgfbr2(flox/flox) to tgfbr2(null/null) in SMC-produced no live SM22-Cre : tgfbr2(flox/flox) pups (P < 0.001). We conclude: (1) "SMC-targeted" Cre lines vary significantly in specificity and efficiency of Cre expression; (2) TGF-beta signaling in the subset of cells that express SM22 alpha is required for normal development; (3) generation of adult mice with absent TGF-beta signaling in SMC remains a challenge. (c) 2006 Elsevier Inc. All rights reserved.