| Description: |
This entry represents the first LIM domain of Lmx1a. Lmx1a belongs to the LHX protein family, which features two tandem N-terminal LIM domains and a C-terminal DNA binding homeodomain. Members of LHX family are found in the nucleus and act as transcription factors or cofactors []. LHX proteins are critical for the development of specialized cells in multiple tissue types, including the nervous system, skeletal muscle, the heart, the kidneys, and endocrine organs, such as the pituitary gland and the pancreas []. Mouse Lmx1a is expressed in multiple tissues, including the roof plate of the neural tube, the developing brain, the otic vesicles, the notochord, and the pancreas []. Human Lmx1a can be found in pancreas, skeletal muscle, adipose tissue, developing brain, mammary glands, and pituitary. The functions of Lmx1a in the developing nervous system were revealed by studies of mutant mouse. In mouse, mutations in Lmx1a result in failure of the roof plate to develop. Lmx1a may act upstream of other roof plate markers such as MafB, Gdf7, Bmp 6, and Bmp7. Further characterization of these mice reveals numerous defects including disorganized cerebellum, hippocampus, and cortex; altered pigmentation; female sterility; skeletal defects; and behavioural abnormalities [, , ]. Within pancreatic cells, the Lmx1a protein interacts synergistically with the bHLH transcription factor E47 to activate the insulin gene enhancer/promoter [].As in other LIM domains, this domain family is 50-60 amino acids in size and shares two characteristic zinc finger motifs. The two zinc fingers contain eight conserved residues, mostly cysteines and histidines, which coordinately bond to two zinc atoms. LIM domains function as adaptors or scaffolds to support the assembly of multimeric protein []. |
