The midregion, nuclear localization sequence, and C terminus of PTHrP regulate skeletal development, hematopoiesis, and survival in mice.
The functions of parathyroid hormone-related protein (PTHrP) on morphogenesis, cell proliferation, apoptosis, and calcium homeostasis have been attributed to its N terminus. Evidence suggests that many of these effects are not mediated by the N terminus but by the midregion, a nuclear localization sequence (NLS), and C terminus of the protein. A knock-in mouse lacking the midregion, NLS, and C terminus of PTHrP (Pthrp(Delta/Delta)) was developed. Pthrp(Delta/Delta) mice had craniofacial dysplasia, chondrodysplasia, and kyphosis, with most mice dying by d 5 of age. In bone, there were fewer chondrocytes and osteoblasts per area, bone mass was decreased, and the marrow was less cellular, with erythroid hypoplasia. Cellular proliferation was impaired, and apoptosis was increased. Runx2, Ocn, Sox9, Crtl1, beta-catenin, Runx1, ephrin B2, cyclin D1, and Gata1 were underexpressed while P16/Ink4a, P21, GSK-3beta, Il-6, Ffg3, and Ihh were overexpressed. Mammary gland development was aberrant, and energy metabolism was deregulated. These results establish that the midregion, NLS, and C terminus of PTHrP are crucial for the commitment of osteogenic and hematopoietic precursors to their lineages, and for survival, and many of the effects of PTHrP on development are not mediated by its N terminus. The down-regulation of Runx1, Runx2, and Sox9 indicates that PTHrP is a modulator of transcriptional activation during stem cell commitment.
Toribio
Ramiro E
RE
Department of Veterinary Clinical Sciences, The Ohio State University, 601 Vernon Tharp St., Columbus, OH 43210, USA. toribio.1@osu.edu
Brown
Holly A
HA
Novince
Chad M
CM
Marlow
Brandlyn
B
Hernon
Krista
K
Lanigan
Lisa G
LG
Hildreth
Blake E
BE
Werbeck
Jillian L
JL
Shu
Sherry T
ST
Lorch
Gwendolen
G
Carlton
Michelle
M
Foley
John
J
Boyaka
Prosper
P
McCauley
Laurie K
LK
Rosol
Thomas J
TJ
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D001842:Bone and Bones / Q000166:cytology* / Q000473:pathology; D019902:Chondrocytes / Q000166:cytology / Q000473:pathology; D005260:Female; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D055879:Gene Knock-In Techniques; D005804:Genes, Lethal; D006410:Hematopoiesis; D007124:Immunoenzyme Techniques; D008297:Male; D008321:Mammary Glands, Animal / Q000254:growth & development / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019913:Nuclear Localization Signals / Q000172:deficiency*; D010006:Osteoblasts / Q000166:cytology / Q000473:pathology; D044162:Parathyroid Hormone-Related Protein / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate
D019913:Nuclear Localization Signals; D044162:Parathyroid Hormone-Related Protein; D012333:RNA, Messenger