GRHL2
Description
The GRHL2 (grainyhead like transcription factor 2) is a protein-coding gene located on chromosome 8.
Grainyhead-like genes are a family of highly conserved transcription factors that are functionally and structurally homologous across a large number of vertebrate and invertebrate species. For an estimated 100 million years or more, this genetic family has been evolving alongside life to fine tune the regulation of epithelial barrier integrity during development, fine-tuning epithelial barrier establishment, maintenance and subsequent homeostasis. The three main orthologues, Grainyhead-like 1, 2 and 3, regulate numerous genetic pathways within different organisms and perform analogous roles between them, ranging from neural tube closure, wound healing, establishment of the craniofacial skeleton and repair of the epithelium. When Grainyhead-like genes are impaired, due to genetic mutations in embryogenesis, it will cause the organism to present with developmental defects that largely affect ectodermal (and sometimes also endodermal) tissues in which they are expressed. These subsequent congenital disorders, including cleft lip and exencephaly, vary greatly in their severity and impact on the quality of life for the affected individual. There is much still to learn about the function of these genes and the more complex roles of Grainyhead-like genes are yet to be discovered.
== Gene Family ==
The Grainyhead-like (Grhl) gene family is a group of highly conserved transcription factors, which work to regulate the expression of specific target genes. Grainyhead (Grh) was originally identified in Drosophila as being implicated within development through its role of regulating numerous genetic pathways. While Drosophila has only one Grh gene, there are three homologues currently known across other species (Grhl1-3). It appears that all members of the Grhl gene family are involved in epidermal barrier integrity, including its formation and repair, and are tightly regulated to prevent physical defects.
Transcription factor playing an important role in primary neurulation and in epithelial development (PubMed:29309642, PubMed:25152456). Binds directly to the consensus DNA sequence 5'-AACCGGTT-3' acting as an activator and repressor on distinct target genes (By similarity). During embryogenesis, plays unique and cooperative roles with GRHL3 in establishing distinct zones of primary neurulation. Essential for closure 3 (rostral end of the forebrain), functions cooperatively with GRHL3 in closure 2 (forebrain/midbrain boundary) and posterior neuropore closure (By similarity). Regulates epithelial morphogenesis acting as a target gene-associated transcriptional activator of apical junctional complex components. Up-regulates of CLDN3 and CLDN4, as well as of RAB25, which increases the CLDN4 protein and its localization at tight junctions (By similarity). Comprises an essential component of the transcriptional machinery that establishes appropriate expression levels of CLDN4 and CDH1 in different types of epithelia. Exhibits functional redundancy with GRHL3 in epidermal morphogenetic events and epidermal wound repair (By similarity). In lung, forms a regulatory loop with NKX2-1 that coordinates lung epithelial cell morphogenesis and differentiation (By similarity). In keratinocytes, plays a role in telomerase activation during cellular proliferation, regulates TERT expression by binding to TERT promoter region and inhibiting DNA methylation at the 5'-CpG island, possibly by interfering with DNMT1 enzyme activity (PubMed:19015635, PubMed:20938050). In addition, impairs keratinocyte differentiation and epidermal function by inhibiting the expression of genes clustered at the epidermal differentiation complex (EDC) as well as GRHL1 and GRHL3 through epigenetic mechanisms (PubMed:23254293). {ECO:0000250|UniProtKB:Q8K5C0, ECO:0000269|PubMed:19015635, ECO:0000269|PubMed:20938050, ECO:0000269|PubMed:20978075, ECO:0000269|PubMed:23254293, ECO:0000269|PubMed:25152456, ECO:0000269|PubMed:29309642, ECO:0000305|PubMed:12175488}
GRHL2 is also known as BOM, DFNA28, ECTDS, PPCD4, TFCP2L3.
Associated Diseases
- Corneal dystrophy, posterior polymorphous, 4
- Ectodermal dysplasia/short stature syndrome
- Deafness, autosomal dominant nonsyndromic sensorineural 28
- Posterior polymorphous corneal dystrophy
