Additional data for the mouse TRPV6 expression atlas

To identify TRPV6 expression in the whole mouse with a cellular resolution we took advantage of TRPV6-IRES-Cre knock-in mice crossed with the enhanced ROSA26-τGFP reporter line. In the resulting TRPV6-IC/eR26-τGFP animals, TRPV6-expressing cells are labeled with τGFP. Data were collected from organs prepared from fixed experimental adult and juvenile TRPV6-IC/eR26τGFP and Cre-negative eR26-τGFP control animals of both sexes. Organ cryosections from each age and sex were stained for GFP and imaged with a slide scanner. Here, we describe reporter gene expression in a large number of tissues. We also document the absence of τGFP signal in the corresponding Cre-negative control tissues, including controls for the TRPV6 expression data described in [1]. The data reported here and in [1] constitute the TRPV6 expression atlas for the mouse. Our data offer a wealth of information to enable investigation of the functional role of TRPV6 channels in different tissues.


a b s t r a c t
To identify TRPV6 expression in the whole mouse with a cellular resolution we took advantage of TRPV6-IRES-Cre knockin mice crossed with the enhanced ROSA26-τ GFP reporter line. In the resulting TRPV6-IC/eR26-τ GFP animals, TRPV6expressing cells are labeled with τ GFP. Data were collected from organs prepared from fixed experimental adult and juvenile TRPV6-IC/eR26 τ GFP and Cre-negative eR26-τ GFP control animals of both sexes. Organ cryosections from each age and sex were stained for GFP and imaged with a slide scanner. Here, we describe reporter gene expression in a large number of tissues. We also document the absence of τ GFP signal in the corresponding Cre-negative control tissues, including controls for the TRPV6 expression data described in [1] . The data reported here and in [1] constitute the TRPV6 expression atlas for the mouse. Our data offer a wealth of information to enable investigation of the functional role of TRPV6 channels in different tissues.  Table   Subject Molecular Biology Specific subject area Mapping of TRPV6 expression in the mouse with cellular resolution by analyzing fluorescently labeled cryosections acquired from TRPV6 reporter mice and comparing them to control tissues. Type of data Image Figure  How the data were acquired Data were acquired from organs dissected from adult and juvenile TRPV6-IRES-Cre/eROSA26-τ GFP animals of both sexes and Cre-negative eROSA26-τ GFP controls. Images of GFP-stained sections from these organs were imaged with an AxioScan slide scanner (Zeiss) using the ZenBlue software. Data format Analyzed Parameters for data collection Data were collected from GFP-stained cryosections prepared from fixed mouse organs of experimental adult and juvenile TRPV6-IRES-Cre/eROSA26-τ GFP and Cre-negative eROSA26-τ GFP control animals of both sexes. Description of data collection Experimental adult and juvenile TRPV6-IRES-Cre/eROSA26-τ GFP and eROSA26-τ GFP control animals of both sexes were transcardially perfused with 4% paraformaldehyde and organs were dissected. Cryosections of organs were stained with an antiserum against GFP and imaged with the AxioScan slidescanner from Zeiss with ZenBlue software.

Value of the Data
• Generation of reporter mouse strains will help understanding gene expression in an organism-wide manner with a single cell resolution. • Data provide an unprecedented wealth of information to investigate the physiological function of defined genes in individual cells/organs in vivo . • Expression atlas can be used by other researchers to identify TRPV6-expressing cell types in different or gans of interest • Data can be used as a reference for further investigation including primary cell isolation

Data Description
Data were collected from adult and juvenile TRPV6-IC/eROSA26-τ GFP male and female reporter (Cre + ) and control animals (Cre-). If not otherwise stated, we did not detect any gross gender or age differences.
Beginning with the nose, we did neither detect reporter gene expression in sensory neurons of the vomeronasal organ (VNO) ( Fig. 1 A-D) nor the main olfactory epithelium (MOE) ( Fig. 2 A-D). Below the olfactory epithelium, we identified reporter gene-expressing cells in the mucosa ( Fig. 1 A-D and Fig. 2 A-D). Next to the olfactory epithelium, we found high prismatic τ GFP + cells in the enamel-secreting cell population ( Figs. 1 and 2 ). Please note that we detected more τ GFP cells in adult animals in the epithelial cell layer next to the incisors when compared to juvenile animals. The observed difference in cell number reflects the lower number of cells showing TRPV6 promotor activity indicating reduced a need for Ca 2 + signals in these cells during early development. We did not detect any reporter gene expression in control tissues ( In the tongue's lamina propria , we identified reporter gene expression in mucous and serous glands ( Fig. 3 A-D). We did not detect τ GFP signal in the tongue of control animals ( We observed τ GFP + cells in a subset of myoepithelial cells in the glands lining the trachea in both adults and juveniles. We did not detect any reporter gene-expressing cells in control animals ( Fig. 7 ). We observed scattered τ GFP + cells with a small cytoplasm in the lung of experimental but not control animals ( Fig. 8 ).
In the gastrointestinal tract, reporter gene expression was observed only in few sub compartments in specific cell types. In the stomach, we detected τ GFP expression in the glandular part in columnar surface epithelial cells, in a subset of acid-secreting parietal cells and in high prismatic epithelial cells in the gastric glands. We did neither detect reporter gene expression in the non-glandular part nor in control tissue ( Fig. 9 ). We also observed reporter gene expression in a subset of high prismatic epithelial cells in the duodenum ( In the gallbladder, we detected sparse τ GFP + cells in epithelial cells of the mucosa, which were absent in control animals ( Fig. 12 ). We detected reporter gene expression in the medulla and in the cortex of the kidney which were not part of the glomerulus. We did not detect any age-differences and no reporter gene expression was observed in control tissues ( Fig. 13 ). We did not detect reporter gene expression in the adrenal gland at any stage analyzed ( Fig. 14 ). In our original research article (Wartenberg et al. Cell Calcium 100:102481, 2021), we described TRPV6 expression in the salivary gland, the thyroid gland, the cecum, the pancreas, the epididymis, the prostate and the uterus by fluorescent labeling in TRPV6 reporter animals and confirmed by mass spectrometry. Here we corroborate the specificity of the fluorescent labeling by documenting the absence of signal in tissue prepared from reporter animals ( Figs. 15 -18 ).

Experimental Design, Materials and Methods
TRPV6-IRES-Cre (TRPV6-IC) animals were generated as described [2] and bred to enhanced-