Monocyte chemoattractant protein 1 in luteolysis.

Monocyte chemoattractant protein 1 (MCP-1) is a member of the chemokine family of cytokines which are involved in leukocyte physiology and trafficking. Interest in the role of inflammatory cells and their cytokine products in luteolysis has been increasing and there is mounting evidence demonstrating that MCP-1 is involved in luteolysis. Cell sources of MCP-1, such as endothelial cells, are abundant in late stage luteal tissue. Increased amounts of mRNA encoding MCP-1 are found after luteolysis in sheep, pigs, cows, rats and women and its up-regulation is associated with an increase in macrophages within the corpus luteum, indicating that MCP-1 may act as an inflammatory mediator during luteal regression. Luteolytic substances (prolactin in rats and prostaglandin F2alpha in ruminants) appear to be involved in increased expression of MCP-1 within the corpus luteum, although it is unclear whether this is a direct or indirect effect. Cytokines produced within the corpus luteum around luteolysis may also be involved in regulating MCP-1 expression. The field of chemokine biology is expanding rapidly and MCP-1, as well as other chemokines yet to be investigated, may prove to be an important link between the hormonal and cellular events within the corpus luteum around the time of luteolysis.

An olfactory receptor gene is located in the extended human beta-globin gene cluster and is expressed in erythroid cells.

An olfactory receptor gene was identified near the 3' breakpoint of a naturally occurring deletion (HPFH-1) in the human beta-globin gene cluster on chromosome 11p15.5. The gene encodes an amino acid sequence that is 40 to 51% identical to that of a set of olfactory receptors that have only recently been identified as a distinct family of receptors. There are two orthologous genes in the mouse that encode amino acid sequences that are 73 and 71% identical, respectively, to that encoded by the human gene. This olfactory receptor gene is expressed at the RNA level in human and murine erythroid cells at all stages of development. This aberrant expression is probably due to the location of the gene in the transcriptionally active chromatin domain of the extended beta-globin gene cluster in erythroid cells.

Immune cells and cytokine production in the bovine corpus luteum throughout the oestrous cycle and after induced luteolysis.

Immune cells and their cytokine products have powerful local effects within body tissues. There has been great interest in the potential role of these cells, not only during destruction of the corpus luteum but also during its functional lifespan. In this study, lymphocytes, macrophages and major histocompatibility complex class II molecules were quantified using immunohistochemistry and the reverse transcription-polymerase chain reaction was used to detect mRNA for tumour necrosis factor alpha and interferon gamma within corpora lutea from three groups of cows: (1) corpora lutea collected at an abattoir and assessed visually into four stages (stage I (days 1-5), stage II (days 6-12), stage III (days 13-18) and stage IV (days 19-21) of the oestrous cycle); (2) corpora lutea collected around natural luteolysis (days 14-20); and (3) corpora lutea collected 6, 12 and 24 h after prostaglandin F 2 alpha-induced luteolysis. The numbers of T lymphocytes (CD5+ and CD8+) were significantly higher (P < 0.05) at stage IV and from day 16 onwards, before functional luteolysis. There were significantly higher numbers (P < 0.01) of macrophages at stages I, III and IV compared with stage II in visually staged tissue. Major histocompatibility complex class II molecules were increased (P < 0.05) at stages I and IV compared to stage II and at all times after induced luteolysis. Using reverse transcription-polymerase chain reaction, mRNA encoding tumour necrosis factor alpha and interferon gamma was detected in all luteal tissue collected around natural luteolysis and after induced luteolysis. These findings, particularly the increase in T lymphocytes before functional luteolysis, provide further evidence of a significant role for the immune system in affecting reproductive function in cows.

Expression of monocyte chemoattractant protein-1 in the bovine corpus luteum around the time of natural luteolysis.

Monocyte chemoattractant protein (MCP-1) is a specific chemoattractant for monocytes/macrophages that could have a role in the influx of macrophages into the corpus luteum (CL) during structural luteolysis. In this study, reverse transcription-polymerase chain reaction and in situ hybridization were used to investigate MCP-1 mRNA expression in CL collected from 18 heifers between Days 15 and 20 of the estrous cycle. There was expression of mRNA encoding MCP-1 in luteal tissue from all cows; however, expression was greater in animals that had undergone luteolysis at the time of CL collection as compared to animals in which the CL was still functional. Similarly, in situ hybridization showed greater expression of mRNA encoding MCP-1 in CL after functional luteolysis. There was also evidence of increased MCP-1 mRNA expression in an animal with a functional CL where the systemic concentration of prostaglandin F2alpha metabolite was high at the time of tissue collection. T lymphocyte populations, identified by immunohistochemistry, had a distribution similar to that of cells expressing MCP-1 mRNA within the CL, but other cell types were also involved. These results demonstrate an increase in MCP-1 mRNA after functional luteolysis in the cow, which may be related to the influx of macrophages that occurs at this time.

Clinical and molecular characterization of patients with distal 11q deletions.

Jacobsen syndrome is caused by segmental aneusomy for the distal end of the long arm of chromosome 11. Typical features include mild to moderate psychomotor retardation, trigonocephaly, facial dysmorphism, cardiac defects, and thrombocytopenia, though none of these features are invariably present. To define the critical regions responsible for these abnormalities, we studied 17 individuals with de novo terminal deletions of 11q. The patients were characterized in a loss-of-heterozygosity analysis using polymorphic dinucleotide repeats. The breakpoints in the complete two-generation families were localized with an average resolution of 3.9 cM. Eight patients with the largest deletions extending from 11q23.3 to 11qter have breakpoints, between D11S924 and D11S1341. This cytogenetic region accounts for the majority of 11q- patients and may be related to the FRA11B fragile site in 11q23.3. One patient with a small terminal deletion distal to D11S1351 had facial dysmorphism, cardiac defects, and thrombocytopenia, suggesting that the genes responsible for these features may lie distal to D11S1351. Twelve of 15 patients with deletion breakpoints as far distal as D11S1345 had trigonocephaly, while patients with deletions distal to D11S912 did not, suggesting that, if hemizygosity for a single gene is responsible for this dysmorphic feature, the gene may lie distal to D11S1345 and proximal to D11S912.

Loss of heterozygosity in cervical carcinoma: subchromosomal localization of a putative tumor-suppressor gene to chromosome 11q22-q24.

Infection of cervical epithelial cells with so-called "aggressive" subtypes of human papilloma virus (HPV) appears to be an important factor in the etiology of cervical carcinoma. However, mounting evidence suggests that additional genetic changes are required for progression to an invasive carcinoma. Functional studies have shown that human chromosome 11 contains a gene or genes capable of suppressing tumorigenicity in cell lines derived from different histopathological types of cervical carcinoma, suggesting that aberration of this gene(s) may represent at least one of the additional changes required for tumorigenic progression. To identify the likely chromosomal position of this gene(s), we have carried out a systematic genetic analysis of chromosome 11 in the primary tumors of 32 patients with cervical carcinoma. Sixteen highly polymorphic markers, 10 of which were based on simple sequence repeats typed by PCR, were used to compare matched DNA samples from noninvolved tissue and portions of tumor tissue highly enriched for neoplastic cells by the cryostat-sectioning technique. Of the 32 patients examined, 14 (44%) demonstrated clonal genetic alterations resulting in loss of heterozygosity for one or more markers. Seven of the clonal genetic alterations on chromosome 11 were specific to the long arm, and the overlap between these and other allelic deletions suggests that a suppressor gene(s) relevant to cervical carcinoma maps to chromosome 11q22-q24.

A structurally abnormal erythropoietin receptor gene in a human erythroleukemia cell line.

Restriction endonuclease mapping demonstrates a 3' end deletion of one erythropoietin receptor (EpoR) gene in TF-1 cells, a human erythroleukemia cell line that overexpresses the EpoR and proliferates in response to erythropoietin (Epo). EpoR mRNA transcripts are highly abundant and normal in size. These findings raise interesting questions about the possible role of this EpoR gene abnormality in the pathogenesis of the erythroleukemia from which this cell line was derived. This is the first report of an abnormal human erythropoietin receptor gene.

Genomic organization of the human erythropoietin receptor gene.

Erythropoietin (EPO) mediates the growth and differentiation of erythroid progenitors through its interaction with a specific receptor. Using a partial cDNA clone for the murine erythropoietin receptor, we isolated a human genomic clone containing the erythropoietin receptor gene. The coding region of the human EPO receptor gene is contained within eight exons spanning approximately 6 kb. The human gene has a great deal of structural similarity and sequence homology with the murine gene. The murine gene also has eight exons, although the size of each intron is somewhat different. The locations at which the introns interrupt the coding sequence are conserved precisely. The genomic organization of the EPO receptor gene is also shown to be homologous to the genomic organization of the IL-2 receptor beta chain gene. The sequence of 1.1 kb of 5' flanking DNA was characterized and contains consensus sequences for both Sp1 and GATA-1 binding sites and an initiator (Inr)-like element, but lacks both a canonical TATA box and the CACCC consensus sequence found in the murine gene.

The gene for the human erythropoietin receptor: analysis of the coding sequence and assignment to chromosome 19p.

The full-length coding sequence of the human erythropoietin receptor has been assembled from cDNA and genomic DNA. The derived 508 amino acid sequence is 82% identical to the murine erythropoietin (Epo) receptor with one single residue gap in alignment. There is no major structural difference between the human and murine receptor molecules. Nucleotide sequence homology is, as expected, very high within the coding domain. Unexpectedly, there are two distinct, short stretches of 3' untranslated sequence homology between human and murine cDNAs. The functional significance of this sequence conservation is unknown. The human Epo receptor gene is localized to human chromosome 19p by in situ hybridization. This chromosome assignment is confirmed by hybridization to a panel of sorted human chromosomes.

Sequence analysis of the gamma-globin gene locus from a patient with the deletion form of hereditary persistence of fetal hemoglobin.

The gamma-globin genes from a patient homozygous for a deletion form of hereditary persistence of fetal hemoglobin (HPFH-1) have been cloned and sequenced. The DNA sequence of the patient's gamma-globin genes corresponds to a previously identified sequence framework (chromosome A) with the exception of 10 base changes. Seven of these base changes can be attributed to normal allelic variation generated by small gene conversion events. The remaining three base changes are present in a 0.76 kb HindIII fragment containing a putative enhancer located 3' to the A gamma-globin gene. The same three base changes have also been described in the Seattle variant of nondeletion HPFH. We have analyzed 16 alleles from non-HPFH individuals and five alleles from individuals with nondeletion or deletion HPFH for the presence of these base changes by polymerase chain reaction amplification of cloned or chromosomal DNA and hybridization to allele-specific oligonucleotide probes. Although these base changes were found in an individual with HPFH-2, they were not found in the DNA from two patients with nondeletion HPFH. More importantly, all three base changes were detected in DNA from five non-HPFH individuals and appear to be common in blacks. We conclude that these base changes do not correlate with an HPFH phenotype and that the significant mutation in HPFH-1 is the deletion of over 100 kb of genomic DNA.