About Left-Right Determination Factor:
This gene is part of the TGF-beta family of proteins. This gene is closely linked to both a related family member and a related pseudogene.
Left-Right Determination Factor Identification
The identification of TDF was carried out in 1989, thanks to the study of human individuals whose phenotypic sex is in discordance with the chromosomal sex. Men with two Xs (46, XX) or women with one X and one Y (46, XY). These individuals phenotypically male and carrying a karyotype 46, XX, contained in their genome a sequence originating from the Y chromosome. Analysis of this DNA segment showed a coding sequence which was called: "sex-determining region" of the Y chromosome or SRY (Sex-determining Region of Y chromosome).
Left-Right Determination Factor Structure
This gene is located on the short arm of the human Y chromosome and meets the characteristics expected of a "TDF''. This gene is conserved on the Y chromosome of many species of mammals. The protein deduced from the SRY gene has a domain allowing its binding to DNA.
Left-Right Determination Factor Function
The establishment of this right-left polarity (DG), in mice in particular, is manifested by the specification of the left side in the embryo before the onset of organogenesis. Four key steps govern this process. The first event is the induction of an asymmetric signal at the level of the embryonic node, probably via the triggering of a current, oriented from right to left and created by the rotation of the cilia of the ventral cells of the node. This signal then propagates to the mesoderm of the left lateral lamina. There transiently activates a series of conserved genes in vertebrates. The products of these genes allow the translation of this asymmetric signal into morphological differences during organogenesis.