Identification Of Homeobox Genes Research Articles

Omics exploration of placental pathologies and development: tissues, cells and genes

s / Placenta 34 (2013) A1–A99 A6 majority of FGR cases remain idiopathic. These idiopathic FGR pregnancies are frequently associatedwith placental insufficiency, possibly as a result of placental maldevelopment. Understanding the molecular mechanisms of abnormal placental development in idiopathic FGR is therefore of increasing importance. The focus of our studywas to understand the role of homeobox gene transcription factors in abnormal placental development associatedwith human idiopathic FGR. The strategy we have employed has resulted in the identification of homeobox genes, which are expressed in normal placental development and that showed altered expression in FGR. Functional assays following target gene inactivation or over-expression to mimic FGR in cultured cells demonstrated that homeobox genes control important functions inplacental cells. The discoveryof targets of homeobox genes has revealed genes, and pathways, not previously implicated in FGR. These target genes and pathways will be further assessed for their therapeutic anddiagnostic potential for clinicalmanagementof idiopathic FGR in future. http://dx.doi.org/10.1016/j.placenta.2013.06.022 PL5.4. OMICS EXPLORATION OF PLACENTAL PATHOLOGIES AND DEVELOPMENT: TISSUES, CELLS AND GENES

Isolation and identification of homeobox genes from the human placenta including a novel member of the Distal-less family, DLX4

We have carried out a DNA binding site screen of a 32-week human placental cDNA library using a consensus homeodomain binding site as a probe. This study represents the first library screen carried out to isolate homeobox genes from the human placenta. We have shown that three homeobox genes known to be expressed in the embryo, HB24, GAX and MSX2 are also expressed in the placenta. We have also identified a novel homeobox gene, DLX4, that shows 85% sequence identity with the homeodomain encoded by the Drosophila Distal-less ( Dll) gene. DLX4 therefore represents a new member of the Distal-less family of homeobox genes. This is the first evidence that members of the Distal-less family of homeobox genes are expressed in the placenta. Using fluorescence in situ hybridisation (FISH), DLX4 has been assigned to human chromosome 17q21–q22. This places DLX4 in the same region of chromosome 17 as another member of the Distal-less family, DLX3 ( Scherer et al., 1995), and the HOX-B homeobox gene cluster ( Acampora et al., 1989; Boncinelli et al., 1991). Members of the Distal-less family ( DLX1 and DLX2; DLX5 and DLX6) are found as closely linked pairs on human chromosomes ( Simeone et al., 1994). We predict that DLX3 and DLX4 are closely linked and have arisen through gene duplication and divergence from a common ancestral precursor.

Identification of homeobox genes expressed during the process of rat liver regeneration after partial hepatectomy

Identification of homeobox genes expressed during the process of rat liver regeneration after partial hepatectomy

Identification of homeobox genes expressed during the process of rat liver regeneration after partial hepatectomy.

Homeobox (HBox) genes are well-known to be involved in development and differentiation. To ascertain a role of HBox genes in the process of liver regeneration, we identified HBox genes expressed at various times after partial hepatectomy in rats (at 0 hr, 1 hr, 2 days, and 4 days) by using reverse transcription-polymerase chain reaction (RT-PCR), cloning, and sequencing techniques. By the competitive RT-PCR method using generic primers, expression levels of HBox genes in regenerating livers were estimated at as low as only 0.4-2% of that in 14-day embryonic liver; however, we identified multiple HBox genes at different stages. Comparing sets of HBox genes identified at different stages, we could find two candidates of stage specifically expressed HBox genes (one rat caudal-related gene, RCdx-3, stimulated at 1 hr, and one rat Hox gene, RHoxB5, repressed after hepatectomy) and continuous expression of five Hox genes (RHoxA1, A4, A5, B2, and B3) before and after hepatectomy. These HBox genes are considered to correlate with the process of liver regeneration.