Generation and characterization of Atoh1‐Cre knock‐in mouse line

Abstract

Summary Atoh1 encodes a basic helix-loop-helix (bHLH) transcription factor required for the development of the inner ear sensory epithelia, the dorsal spinal cord, brainstem, cerebellum, and intestinal secretory cells. In this study to create a genetic tool for the research on gene function in the ear sensory organs, we generated an Atoh1-Cre knock-in mouse line by replacing the entire Atoh1 coding sequences with the Cre coding sequences. Atoh1Cre/+mice were viable, fertile, and displayed no visible defects whereas the Atoh1Cre/Cremice died perinatally. The spatiotemporal activities of Cre recombinase were examined by crossing Atoh1-Cre mice with the R26R-lacZ conditional reporter mice. Atoh1-Cre activities were detected in the developing inner ear, the hindbrain, the spinal cord, and the intestine. In the inner ear, Atoh1-Cre activities were confined to the sensory organs in which lacZ expression is detected in nearly all of the hair cells and in many supporting cells. Thus, Atoh1-Cre mouse line serves as a useful tool for the functional study of genes in the inner ear. In addition, our results demonstrate that Atoh1 is expressed in the common progenitors destined for both hair and supporting cells.

Fine-tuning of Notch signaling sets the boundary of the organ of Corti and establishes sensory cell fates

“…As this column of Atoh1, Lfng, Mfng, Jag2 and Dll1 -expressing progenitors develops, we propose that a second fate decision between an inner hair cell and an inner phalangeal cell is achieved by conventional hair cell-supporting cell lateral inhibition mediated through Dll1 and Jag2 (Figure 6C, green cells; Hicks et al (2000); Van de Walle et al, 2011). Our current data, previous expression studies (Chen et al, 2002; Cai et al, 2013) and previous Atoh1 lineage tracing showing inner phalangeal cells derived from Atoh1- expressing cells (Yang et al, 2010) suggests this entire column of cells initially expresses early hair cell genes such as Atoh1 and Mfng. Since we only observe a conversion of inner phalangeal cells to inner hair cells when Notch signaling is strongly reduced (in Notch1 mutants or at high doses of Notch inhibitors; Figures 3 and 5), we suggest this second phase of Notch signaling involves high levels of Notch signaling and is resistant to subtle manipulation of Notch signals.…”

The spatio-temporal domains of Frizzled6 action in planar polarity control of hair follicle orientation

“…6A; Yang et al, 2010). Using the Math1-Cre line, we designed an experimental strategy analogous to that described above for hair follicles and inter-follicular epidermis (Fig.…”

“…The following mouse alleles were also used: Fz6 − (Guo et al, 2004), R26-LSL-FZ6 (Hua et al, 2014a,b), Hprt-LSL-tdT (Wu et al, 2014), K17-GFP (Bianchi et al, 2005), Sox2-Cre (Hayashi et al, 2002), K14-Cre (Dassule et al, 2000; JAX 004782), Cdx2-Cre (Hinoi et al, 2007; JAX 009350), Emx1-Cre (Gorski et al, 2002; JAX 005628), Shh-Cre (Harfe et al, 2004; JAX 005622), Math1(Atoh1)-Cre (Yang et al, 2010; a kind gift of Dr. Lin Gan, University of Rochester), Vangl2 CKO (Copley et al, 2013), and Vangl2 − (Smallwood, Williams, and Nathans, unpublished). Mice were handled and housed according to the approved Institutional Animal Care and Use Committee (IACUC) protocol M013M469 of the Johns Hopkins Medical Institutions.…”

Deletion of Brg1 causes abnormal hair cell planer polarity, hair cell anchorage, and scar formation in mouse cochlea

“…Animal management was performed strictly in accordance with the standards of the Animal Ethics Committee of Shandong University (Permit Number: ECAESDUSM 20123004). Brg1 flox / flox  59 and Atoh1-Cre 60 mouse lines were maintained on a mixed genetic background and genotyped as described previously. Brg1 flox / flox females were mated with Atoh1-Brg1 flox /+ to generate Atoh1-Brg1 −/− mice.…”