The human and mouse orthologous LIM-only proteins respectively encoded in chromosome 6 and 17 show a different expression pattern.
Thymocytes interact with various subpopulations of thymic epithelial cells (TECs) at different stages of their development. To identify new molecules specifically expressed in TECs and/or thymic nurse cells (TNCs), we used representational difference analysis. We identified a LIM protein located on mouse chromosome 17 (m17TLP) and belonging to the family of the LIM-only proteins (LIMo). We found a new splice variant in addition to the two described A and B isoforms. The three alternative species of m17TLP are found strictly in the thymic stroma. This protein is expressed on a subpopulation of TECs and TNCs. Strikingly, we found that the human ortholog of m17TLP, located on chromosome 6 (h6LIMo), is expressed in most tissues, but not in skeletal muscle. We have identified four human splice variants of h6LIMo which differ in their carboxy-terminal regions. The sequence comprising the genomic structure suggests that CRP2 is the closest known relative of m17TLP. Although the human and mouse nucleotide sequences are 88-97% homologous, this homology is reduced to 47% in the promoter regions, which strongly suggests that their differential expression is related to their promoter regulatory activity.
Casrouge
Armanda
A
Laboratoire de Biologie Moléculaire du Gène, Inserm U277-Institut Pasteur, 75724-Paris cedex 15, France.
Veitia
Reiner
R
Kirchner
Jacqueline
J
Bevan
Michael J
MJ
Kanellopoulos
Jean
J
D017398:Alternative Splicing; D000818:Animals; D002896:Chromosomes, Human, Pair 6 / Q000235:genetics*; D033481:Chromosomes, Mammalian / Q000235:genetics*; D004847:Epithelial Cells / Q000378:metabolism; D015870:Gene Expression; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D060850:LIM-Homeodomain Proteins; D051379:Mice; D009928:Organ Specificity; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors
D018398:Homeodomain Proteins; C085473:LHX1 protein, human; D060850:LIM-Homeodomain Proteins; C499523:Lhx1 protein, mouse; D014157:Transcription Factors