PT  - JOURNAL ARTICLE
AU  - Fabian, Peter
AU  - Tseng, Kuo-Chang
AU  - Smeeton, Joanna
AU  - Lancman, Joseph J.
AU  - Dong, P. Duc Si
AU  - Cerny, Robert
AU  - Crump, J. Gage
TI  - Lineage analysis reveals an endodermal contribution to the vertebrate pituitary
AID  - 10.1126/science.aba4767
DP  - 2020 Oct 23
TA  - Science
PG  - 463--467
VI  - 370
IP  - 6515
4099  - http://science.sciencemag.org/content/370/6515/463.short
4100  - http://science.sciencemag.org/content/370/6515/463.full
SO  - Science2020 Oct 23; 370
AB  - Placodes are specializations of the head ectoderm that are considered the source of many vertebrate novelties, including the nose, lens, ear, and hormone-producing portion of the pituitary. However, the presence of a pituitary-like structure in nonvertebrate chordates, derived instead from the endoderm, had suggested that the pituitary may predate placodes. Fabian et al. performed lineage tracing, time-lapse imaging, and single-cell messenger RNA sequencing to show that both endodermal and ectodermal cells can generate hormone-producing cells of the zebrafish pituitary. These experiments support that the vertebrate pituitary arises through interactions of an ancestral endodermal protopituitary with newly evolved placodal ectoderm.Science, this issue p. 463Vertebrate sensory organs arise from epithelial thickenings called placodes. Along with neural crest cells, cranial placodes are considered ectodermal novelties that drove evolution of the vertebrate head. The anterior-most placode generates the endocrine lobe [adenohypophysis (ADH)] of the pituitary, a master gland controlling growth, metabolism, and reproduction. In addition to known ectodermal contributions, we use lineage tracing and time-lapse imaging in zebrafish to identify an endodermal contribution to the ADH. Single-cell RNA sequencing of the adult pituitary reveals similar competency of endodermal and ectodermal epithelia to generate all endocrine cell types. Further, endoderm can generate a rudimentary ADH-like structure in the near absence of ectodermal contributions. The fish condition supports the vertebrate pituitary arising through interactions of an ancestral endoderm-derived proto-pituitary with newly evolved placodal ectoderm.