LIM homeo box genes encode a family of transcription regulators that share common structural features. They all
contain 2 tandemly repeated cysteine-rich double-zinc finger motifs called LIM domains, in addition to a homeodomain.
Whereas the homeodomain is a DNA-binding domain, the LIM domains are essential for regulating the activity of these
molecules by interacting with other proteins. At least 40 members of this family have been identified in vertebrates and invertebrates, and are
distributed into 4 groups according to the number of LIM domains and to the presence of domains such as
homeodomains and kinase domains.
General function
Nucleic acid binding, DNA binding, Transcription factor
Comment
Cellular localization
Nuclear
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Ovarian function
Germ cell development, gonadogenesis
Comment
Birk OS, et al. reported the LIM homeobox gene Lhx9 is essential for mouse gonad formation.
During mammalian embryonic development, the ovaries and testes develop from somatic cells of the
urogenital ridges as indifferent gonads, harbouring primordial germ cells that have migrated there. After
sex determination of the gonads, the testes produce testosterone and anti-Mullerian hormone which
mediate male sexual differentiation, and the female developmental pathway ensues in their absence. Transcripts of the LIM homeobox gene Lhx9 are present in urogenital ridges of mice at
embryonic day 9.5; later they localize to the interstitial region as morphological differentiation occurs.
Expression regulated by
Comment
Ovarian localization
urogenital ridge
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Follicle stages
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Phenotypes
Mutations
1 mutations
Species: mouse
Mutation name: None
type: null mutation fertility: infertile - ovarian defect Comment:Birk OS, et al. reported that , in
mice lacking Lhx9 function, germ cells migrate normally, but somatic cells of the genital ridge fail to
proliferate and a discrete gonad fails to form. In the absence of testosterone and anti-Mullerian hormone,
genetically male mice are phenotypically female. The expression of steroidogenic factor 1 (Sf1), a
nuclear receptor essential for gonadogenesis, is reduced to minimal levels in the Lhx9-deficient genital
ridge, indicating that Lhx9 may lie upstream of Sf1 in a developmental cascade. Unlike mice lacking
other genes that mediate early stages of gonadogenesis, Lhx9 mutants do not exhibit additional major
developmental defects. Thus, LHX9 mutations may underlie certain forms of isolated gonadal agenesis in
humans.