Development of a pituitary‐specific cre line targeted to the Pit‐1 lineage

Abstract

Tissue-specific expression of the Cre recombinase is a well-established genetic tool to analyze gene function in specific tissues and cell types. In this report, we describe the generation of a new transgenic line that expresses Cre under the control of the rat growth hormone releasing hormone receptor (rGhrhr) promoter. This promoter, chosen to target the anterior pituitary, drives cre-mediated recombination in cells of the Pit1 lineage, including somatotrophs, lactotrophs, and thyrotrophs. Cre activity is first detected at embryonic day 13.5, and gradually increases to reach high level expression by postnatal day 2. In addition to the pituitary, rGhrhr-cre expression was detected in vibrissae and in hair follicles of the proximal limb, but not in other tissues. The rGhrhr-cre line will be a valuable tool for the study of the development of the pituitary Pit1 lineage and for the study of tumorigenesis involving these cells.

Tissue-specific ablation of Prkar1a causes schwannomas by suppressing neurofibromatosis protein production

“…In line with these data, TEC3KO tumors revealed heavy staining for this marker by immunohistochemistry, even in areas where cell proliferation was not obvious ( Figure W3C ). The heterogeneity of these tumors was further observed by LacZ staining of frozen tissue sections taken from TEC3KO animals carrying the Rosa26 lacZ allele [22]. Analysis of this staining revealed that both cre-positive and cre-negative cells were present in the tumors, further confirming their heterogeneity ( Figure W3D).…”

“…LacZ staining of frozen tissues was performed as described (Yin et al, 2008). Images were visualized on an Olympus BX50 microscope and captured using Spot Basic v4.1 software.…”

“…Samples were analyzed on a microscope (Model BX50; Olympus, Center Valley, PA), and images were captured using Spot Basic v4.1 software. LacZ staining of frozen tissues was performed as described [22] and visualized as above.…”

Rac1 is required for Prkar1a-mediated Nf2 suppression in Schwann cell tumors

“…These mice carried the ROSA26 lacZ reporter allele in order to confirm cre expression by LacZ staining (18) (Supplemental Fig. 1).…”

PRKAR1A and the evolution of pituitary tumors

“…To this end, we produced a mouse line which used the rat GHRH receptor promoter to drive cre expression. This promoter, which is normally specific for the GH-producing pituitary cells [31], enabled expression of cre in cells of the Pit1 lineage, including somatotrophs, lactotrophs, and thyrotrophs [32]. These mice were then crossed with Prkar1a conditional null animals [26] to produce mice with a pituitary-specific knockout of Prkar1a (Prkar1a-pitKO) [33].…”