Bone morphogenetic protein 7 or BMP7 (also known as osteogenic protein-1 or OP-1) is a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the BMP7 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

.

Function

The protein encoded by this gene is a member of the TGF-β

Transforming growth factor

Transforming growth factor is used to describe two classes of polypeptide growth factors, TGFα and TGFβ....

 superfamily. Like other members of the bone morphogenetic protein

Bone morphogenetic protein

Bone morphogenetic proteins are a group of growth factors also known as cytokines and as metabologens . Originally discovered by their ability to induce the formation of bone and cartilage, BMPs are now considered to constitute a group of pivotal morphogenetic signals, orchestrating tissue...

 family of proteins, it plays a key role in the transformation of mesenchymal cells into bone and cartilage. It is inhibited by noggin

Noggin (protein)

Noggin, also known as NOG, is a protein which in humans is encoded by the NOG gene.Noggin inhibits TGF-β signal transduction by binding to TGF-β family ligands and preventing them from binding to their corresponding receptors. Noggin plays a key role in neural induction by inhibiting BMP4, along...

 and a similar protein, chordin, which are expressed in the Spemann-Mangold Organizer. BMP7 may be involved in bone homeostasis

Homeostasis

Homeostasis is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature or pH...

. It is expressed in the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

, kidneys and bladder

Urinary bladder

The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...

.

BMP7 induces the phosphorylation of SMAD1 and SMAD5, which in turn induce transcription of numerous osteogenic genes. It has been demonstrated that BMP7 treatment is sufficient to induce all of the genetic markers of osteoblast

Osteoblast

Osteoblasts are mononucleate cells that are responsible for bone formation; in essence, osteoblasts are specialized fibroblasts that in addition to fibroblastic products, express bone sialoprotein and osteocalcin.Osteoblasts produce a matrix of osteoid, which is composed mainly of Type I collagen...

 differentiation

Cellular differentiation

In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...

 in many cell types.

Role in vertebrate development

BMP7 has been discovered to be crucial in the determination of ventral-dorsal organization in zebrafish. BMP7 causes the expression of ventral phenotypes while its complete inhibition creates a dorsal phenotype. Moreover, BMP7 is eventually partially "turned off" in embryonic development in order to create the dorsal parts of the organism.

In many early developmental experiments using zebrafish, scientists used caBMPR (constitutively active) and tBMP (truncated receptor) to determine the effect of BMP7 in embryogensis. They found that the constitutively active, which causes BMP to be expressed everywhere creates a ventralized phenotype, whereas truncated, dorsalized.

Therapeutic application

Human recombinant BMP7 has surgical uses and is marketed under the brand name OP1 (sold by Olympus, who bought it from Stryker). It can be used to aid in the fusion of vertebral bodies to prevent neurologic trauma. Also in the treatment of tibia

Tibia

The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

l non-union, frequently in cases where a bone graft has failed.

BMP7 also has the potential for treatment of chronic kidney disease.

BMP7 administration has been proposed as a possible treatment for human infertility due to poor response to FSH

FSH

FSH may refer to:* Follicle-stimulating hormone* Fox Sports Houston, a regional Fox Sports Net affiliate station for the Houston, Texas area* Facioscapulohumeral muscular dystrophy* International Civil Aviation Organisation code for Flash Airlines...

treatment.

Promotion of brown fat

It was discovered that mice injected with BMP7 increased their production of "good" brown fat cells, while keeping their levels of the normal white fat cells constant. A BMP7 therapy for obesity in humans may be developed as a result.