Table 1.
Summary of markers potentially involved in pituitary stem cells, progenitors, and differentiation
| Gene name | Protein encoded | Main characteristic |
|---|---|---|
| Transcription factors | ||
| Sox2 | SRY-related HMG box transcription factor | Expressed in pituitary marginal zone, stem cell marker in several tissues |
| Sox9 | SRY-related HMG box transcription factor | Might play a role in the transition between pituitary stem cells/progenitors and transit-amplifying cells |
| Prop1 | Paired homeodomain transcription factor | Expressed in pituitary marginal zone prior to emergence of most differentiated cell types |
| Tpit (Tbx19) | Pituitary T box transcription factor | Promotes corticotroph differentiation |
| Oct4 (Pou5f1) | POU homeodomain transcription factor | Expressed in several tissue stem cells |
| Pou1f1 (Pit1) | POU homeodomain transcription factor | Involved in differentiation of somatolactotroph and thyrotroph lineages |
| Nanog | Homeobox transcription factor | Involved in maintaining stem cell pluripotency |
| Hes1 | Basic helix loop helix transcription factor | Notch downstream target, repressor of cell cycle inhibitors. Expressed in S/G2/M/G1, not in G0 |
| Cell cycle regulators | ||
| Bmi1 | BMI1 polycomb ring finger oncogene | Regulates cell cycle inhibitor genes |
| Cyclin D1 (Ccnd1) | G1/S specific cyclin D1 | Involved in G1/S cell cycle transition |
| Cyclin D2 (Ccnd2) | G1/S specific cyclin D2 | Involved in G1/S cell cycle transition |
| Cyclin E (Ccne1) | Cyclin E | Allows progression to S phase |
| Cdk4 | Cyclin-dependent kinase 4 | Involved in cell cycle G1 phase progression |
| Ki67 | Antigen Ki-67 | Nuclear protein associated with cell proliferation. Marks all steps except G0 |
| Intermediate filament proteins | ||
| Nestin | Type VI intermediate filament protein | Expressed in pituitary marginal zone |
| Gfap | Glial fibrillary acidic protein (intermediate filament protein) | Expressed in folliculostellate cells |
| Cytokeratin 8 (Krt8) | Keratin-containing intermediate filament protein | Expressed in pituitary marginal zone in adulthood |
| Adhesion and cell surface proteins, receptors, and others | ||
| E-cadherin (Cdh1) | Calcium-dependent adhesion molecule (type 1 transmembrane protein) | Might be involved in transition from proliferation to differentiation |
| Epcam (CD326) | Epithelial cell adhesion molecule | Pan-epithelial differentiation antigen expressed in carcinomas |
| CD90 | Thy1 or CD90 (cell surface protein) | Marker of a variety of stem cells |
| Gfra2 | GDNF receptor α 2 | Stem cell marker in testis and ovary. Expressed in pituitary marginal zone |
| S100β | S100 calcium binding protein B | Expressed in folliculostellate cells |
| Sca1(Ataxin1) | Stem cell antigen 1 | Expressed in the side population cells and pericytes |
| c-Kit (CD117) | Cytokine receptor CD117 | Expressed in hematopoietic stem cells |
| Notch1 | Notch 1 (transmembrane receptor) | Involved in progenitor differentiation in CNS |
| Rb | Retinoblastoma | Tumor suppressor gene. Haploinsufficiency increases risk of retinoblastoma in humans and intermediate lobe adenomas in mice |
| AIP | Aryl hydrocarbon receptor interacting protein | Involved in familial pituitary adenomas |