A. Spötter

Molecular characterization and chromosome assignment of the porcine gene for leukemia inhibitory factor LIF

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine involved in early conceptus development in pig. We isolated a PAC clone containing the porcine LIF gene and determined the complete DNA sequence of the gene, which spans about 6.3 kb and consists of five exons including three alternative first exons (1D, 1M, 1T) spliced onto common second and third exons. The LIF-D transcript encodes a protein of 202 amino acids sharing 87, 84, and 78% identity with respectively human, ovine, and murine leukemia inhibitory factors. The LIF-M and LIF-T transcripts both encode a truncated protein of 158 amino acids. Two SNP markers within untranslated regions of the LIF cDNA were identified. One SNP is located in the 5′-UTR of the alternative exon 1T while the other SNP is located in the 3′-UTR of exon 3. Based on fluorescence in situ hybridization and radiation hybrid mapping, the porcine LIF gene was assigned to chromosome 14q2.1→q2.2.

Characterization and comparative mapping of the porcine CTSL gene indicates a novel synteny between HSA9q21→q22 and SSC10q11→q12

Cathepsin L (CTSL) is a lysosomal cysteine protease with potent elastase and collagenase activities. Its high activity in the uterine lumen during the period of placental attachment has led to speculation that CTSL may play an important role during embryonic implantation in the pig. Cathepsins have also been implicated in blastocyst implantation in other species like cat, rat and man. We isolated a PAC clone containing the porcine CTSL gene and determined the complete DNA sequence of the gene, which spans about 5.6 kb and consists of eight exons. The CTSL transcript encodes a primary peptide of 334 amino acids sharing 73–78% identity with other mammalian cathepsin L precursor proteins. Based on fluorescence in situ hybridization and radiation hybrid mapping, the porcine CTSL gene was assigned to chromosome 10q11→ q12.

Mapping and microsatellite marker development for the porcine leukemia inhibitory factor receptor (LIFR) and epidermal growth factor receptor (EGFR) genes

Leukemia inhibitory factor receptor (LIFR), epidermal growth factor receptor (EGFR), and their respective ligands have been implicated in regulating growth and development of the early pig conceptus. We isolated a PAC clone containing the porcine gene for LIFR and a BAC clone with the porcine EGFR gene, respectively. On each of these clones one microsatellite marker was identified by sequencing a collection of subclones. These gene-associated markers were evaluated by genotyping of 202 unrelated boars of four different breeds. Based on fluorescence in situ hybridization and radiation hybrid mapping, the porcine LIFR gene was assigned to SSC16q13→q14. The EGFR gene mapped to SSC9q26.

Assignment1 of the porcine inter-α trypsin inhibitor heavy chain 4 (ITIH4) gene to SSC13q2.1→q2.2 by fluorescence in situ hybridization and radiation hybrid mapping

ITIH4 is a glycoprotein that belongs to the inter-·-trypsin inhibitor family of serine protease inhibitors which act as acute phase reactants after trauma (Buchmann et al., 1990). Endometrial gene expression of ITIH4 in pig was detected during oestrus cycle (days 0–18) and early pregnancy (days 10–18). Gene expression of ITIH4 is enhanced during the midluteal phase (days 12 and 15) of the oestrus cycle and the period of trophoblast attachment (days 12–18). It was not detected in day 10 or day 12 pig conceptus tissues (Geisert et al., 1998). Synthesis of the glycoprotein by the uterine epithelium is stimulated by progesterone (Geisert et al., 1995). The role of ITIH4 in uterine function and in the conceptus has not been established. Regulation of cleavage for release of the polypeptide during pregnancy and early conceptus development suggests that it may play a role in conceptus-uterine interactions for the establishment of pregnancy in pigs, probably as an acute phase protein for protection of the uterus from the inflammatory response induced by conceptus attachment to the uterine epithelium (GonzalesRamon et al., 1995; Geisert et al., 1998). In this study, we assigned the ITIH4 gene to SSC13q2.1→q2.2.

Physical mapping and marker development for the porcine glial cells missing homolog 1 (Drosophila) (GCM1) gene.

The murine Gcm1 encodes a transcription factor that is required for placental development. It is expressed in the labyrinth beginning at the time of chorioallantoic fusion. The labyrinth fails to develop in Gcm1–/– mice, resulting in death by embryonic day 10 (E10) (Anson-Cartwright et al., 2000). The essential role of GCM1 in embryonic development in mice implies that GCM1 may also serve a vital function in conceptus-uterine interactions in pigs. Most conceptus mortality in pigs occurs within the first 30 days of gestation. Therefore it is important to identify the genes that affect alterations in conceptus, uterine and placental development and to understand their modes of action and interplay in the way of reciprocal signaling between the blastocyst and the uterus (Geisert and Yelich, 1997). Here we report the chromosomal localization of the porcine GCM1 gene and the identification and characterization of a GCM1 associated microsatellite marker.