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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.

Genetic dominance has long been considered as a qualitative reflection of interallelic interactions. Dominance arises from many multiple sources whose unifying theme is the existence of non‐linear relationships between the genotypic and phenotypic values. One of the clearest examples are dominant negative mutations (DNMs) in which a defective subunit poisons a macromolecular complex. Dominance can also be due to the presence of a heterozygous null allele, as is the case of haploinsufficiency. Dominance can also be influenced by epistatic (interloci) interactions. For instance, a pre‐existing genetic variant can make possible the expression of a pathogenic variant in a seemingly “dominant” fashion. Such interactions, which can make an individual more or less sensitive to a particular pathogenic variant, will also be discussed here. [ABSTRACT FROM AUTHOR]

FOXL2 is a putative transcription factor involved in ovarian development and function. Its mutations in humans are responsible for the blepharophimosis syndrome, characterized by eyelid malformations and premature ovarian failure (POF). Here we have performed a comparative sequence analysis of FOXL2 sequences of ten vertebrate species. We demonstrate that the entire open reading frame (ORF) is under purifying selection leading to strong protein conservation. We also review recent data on FOXL2 transcript and protein expression. FOXL2 has been shown 1) to be the earliest known sex dimorphic marker of ovarian determination/differentiation in vertebrates, 2) to have, at least in mammals, an ovarian expression persisting until adulthood. The conservation of its sequence and pattern of expression suggests that FOXL2 might be a key factor in the early development of the vertebrate female gonad and involved later in adult ovarian function. Finally, we provide arguments for the existence of an alternative transcript in rodents, that may arise from a differential polyadenylation. Although it has only been demonstrated in rodents, its presence/absence in other species deserves further investigation. Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

We have characterized a novel human gene (C14orf1) which codes for a polypeptide homologous to the yeast protein Yer044c. Both the human and yeast proteins are predicted to be highly basic and to present several potential, evolutionarily conserved, transmembrane domains. C14orf1 mRNA was found to be particularly abundant in the adult testis and in several cancer cell lines. The gene maps to chromosome band 14q24. Further investigations should be performed to understand the role of C14orf1 in the testis and the significance of its strong expression in the cell lines studied here. [ABSTRACT FROM AUTHOR]