Quantitative trait loci analysis for growth and carcass traits in a half-sib family of purebred Japanese Black (Wagyu) cattle1

We used a half-sib family of purebred Japanese Black (Wagyu) cattle to locate economically important quantitative trait loci. The family was composed of 348 fattened steers, 236 of which were genotyped for 342 microsatellite markers spanning 2,664 cM of 29 bovine autosomes. The genome scan revealed evidence of 15 significant QTL (<5% chromosome-wise level) affecting growth and carcass traits. Of the 15 QTL, six QTL were significant at the 5% experiment-wise level and were located in bovine chromosomes (BTA) 4, 5, and 14. We analyzed these three chromosomes in more detail in the 348 steers, with an average marker interval of 1.2 cM. The second scan revealed that the same haplotype of the BTA 4 region (52 to 67 cM) positively affected LM area and marbling. We confirmed the QTL for carcass yield estimate on BTA 5 in the region of 45 to 54 cM. Five growth-related QTL located on BTA 14, including slaughter and carcass weights, were positively affected by the same region of the haplotype of BTA 14 (29-51 cM). These data should provide a useful reference for further marker-assisted selection in the family and positional cloning research. The research indicates that progeny design with moderate genotyping efforts is a powerful method for detecting QTL in a purebred half-sib family.

Downregulation of prostaglandin E receptor subtype EP3 during colon cancer development

BACKGROUND AND AIMS

Involvement of prostaglandin E(2) (PGE(2)) receptors EP(1), EP(2), and EP(4) in the formation of aberrant crypt foci (ACF) and/or intestinal polyps has been suggested. In contrast, EP(3) appears to have no influence on the early stages of colon carcinogenesis. In the present study, we examined expression of PGE(2) receptor subtypes EP(1), EP(2), EP(3), and EP(4) in normal colon mucosa and colon cancers, and assessed the contribution of EP(3) to colon cancer development.

METHODS

mRNA expression of PGE(2) receptor subtypes EP(1), EP(2), EP(3), and EP(4) in normal colon mucosa and colon cancers in azoxymethane (AOM) treated mice and rats, and in humans, were examined by reverse transcription-polymerase chain reaction (RT-PCR), quantitative real time RT-PCR, and immunohistochemical analyses. Evaluation of the role of EP(3) was performed by intraperitoneal injection of AOM, using EP(3) receptor knockout mice. Effects of EP(3) receptor activation on cell growth of human colon cancer cell lines were examined using ONO-AE-248, an EP(3) selective agonist. Moreover, EP(3) expression in colon cancer cell lines was analysed with or without 5-aza-2'-deoxycytidine (5-aza-dC) treatment.

RESULTS

Expression levels of EP(1) and EP(2) mRNA were increased in cancer tissues. EP(4) mRNA was constantly expressed in normal mucosa and cancers. In contrast, expression of EP(3) mRNA was markedly decreased in colon cancer tissues, being 5% in mice, 9% in rats, and 28% in humans compared with normal colon mucosa, analysed by quantitative real time RT-PCR. Immunohistochemical staining demonstrated the rat EP(3) receptor protein to be expressed in epithelial cells of normal mucosa and some parts of small carcinomas but hardly detectable in large carcinomas of the colon. Colon cancer development induced by AOM in EP(3) receptor knockout mice was enhanced compared with wild-type mice, with a higher incidence of colon tumours (78% v 57%) and mean number of tumours per mouse (2.17 (0.51) v 0.75 (0.15); p<0.05). Expression of EP(3) mRNA was detected in only one of 11 human colon cancer cell lines tested. Treatment with 5 microM of an EP(3) selective agonist, ONO-AE-248, resulted in a 30% decrease in viable cell numbers in the HCA-7 human colon cancer cell line in which EP(3) was expressed. Treatment with 5-aza-dC restored EP(3) expression in CACO-2, CW-2, and DLD-1 cells but not in WiDr cells, suggesting involvement of hypermethylation in the downregulation of EP(3) to some extent.

CONCLUSION

The PGE(2) receptor subtype EP(3) plays an important role in suppression of cell growth and its downregulation enhances colon carcinogenesis at a later stage. Hypermethylation of the EP(3) receptor gene could occur and may contribute towards downregulating EP(3) expression to some extent in colon cancers.

A new scoring system for Perthes’ disease based on combined lateral and posterior pillar classifications

We have devised a combined pillar score (CPS) system, based on the lateral pillar (LP) and the posterior pillar (PP) classifications, together with the age at onset of Perthes’ disease, and examined its correlation with prognosis. The correlation coefficient of the Catterall classification, LP, PP, and CPS systems with the Stulberg system was 0.39, 0.52, 0.50, and 0.70, respectively. Overall 21 of the 22 hips (95.4%) with a CPS of 0 to 1 point had a good outcome and 12 of the 13 hips (92.3%) with a CPS of 3 points or more had a fair or poor outcome. None with a CPS of 2 points, had a poor outcome. The study shows that an accurate prediction of the prognosis is not possible with the LP classification alone for patients classified as belonging to group B (LP height 50% to 100% of contralateral height). The CPS system does allow accurate prediction of outcome.

Quantitative trait loci analysis for growth and carcass traits in a Meishan x Duroc F2 resource population

We constructed a pig F2 resource population by crossing a Meishan sow and a Duroc boar to locate economically important trait loci. The F2 generation was composed of 865 animals (450 males and 415 females) from four F1 males and 24 F1 females and was genotyped for 180 informative microsatellite markers spanning 2,263.6 cM of the whole pig genome. Results of the genome scan showed evidence for significant quantitative trait loci (<1% genomewise error rate) affecting weight at 30 d and average daily gain on Sus scrofa chromosome (SSC) 6, carcass yield on SSC 7, backfat thickness on SSC 7 and SSC X, vertebra number on SSC 1 and SSC 7, loin muscle area on SSC 1 and SSC 7, moisture on SSC 13, intramuscular fat content on SSC 7, and testicular weight on SSC 3 and SSC X. Moreover, 5% genomewise significant QTL were found for birth weight on SSC 7, average daily gain on SSC 4, carcass length on SSC 6, SSC 7, and SSC X and lightness (L value) on SSC 3. We identified 38 QTL for 28 traits at the 5% genomewise level. Of the 38 QTL, 24 QTL for 17 traits were significant at the 1% genomewise level. Analysis of marker genotypes supported the breed of origin results and provided further evidence that a suggestive QTL for circumference of cannon bone also was segregating within the Meishan parent. We identified genomic regions related with growth and meat quality traits. Fine mapping will be required for their application in introgression programs and gene cloning.

Pruritus-associated response mediated by cutaneous histamine H3 receptors

BACKGROUND

Histamine is one of the most common chemical mediators causing pruritus, and H1 receptor antagonists have been used as a first choice in its treatment. On the other hand, although the presence of H3 receptors has been identified in the skin, few studies have investigated the involvement of H3 receptors on pruritus.

OBJECTIVE

The purpose of this study was to examine whether H3 receptor agonist or antagonist influences the incidence of scratching behaviour in ICR or mast cell-deficient WBB6F1-W/WV mice.

METHODS

The mice were given an intradermal injection of H3 receptor agonist or antagonist into the rostral part of the back, and the occurrence of scratching behaviour at the injected site by the hind paws was counted over 60 min.

RESULTS

H3 receptor antagonists, thioperamide and AQ0145 significantly increased the incidence of scratching behaviour in ICR mice. H3 receptor agonist, (R)-alpha-methylhistamine, had no effect. On the other hand, (R)-alpha-methylhistamine significantly inhibited thioperamide or AQ0145-induced scratching behaviour. In addition, both thioperamide and AQ0145 elicited scratching behaviour in mast cell-deficient WBB6F1-W/WV mice.

CONCLUSION

From these results, it may be concluded that H3 receptors are involved in the modulation of pruritus in the skin, and mast cells are not essential in this response. In addition, H3 receptor agonists can be useful as a novel therapeutic approach against pruritus.

Mapping of 1400 expressed sequence tags in the bovine genome using a somatic cell hybrid panel

A bovine/hamster hybrid cell panel consisting of 30 independent hybrids was developed to locate genes. Polymerase chain reaction analysis of 279 microsatellites on the cattle linkage map in this panel revealed the presence of all chromosomes in either entire or fragmented form. Among primer pairs prepared from bovine 3'-expressed sequence tags (ESTs), 1400 ESTs were assigned to specific chromosomes, of which 1303 were newly assigned in this study, and mapped 854 (61%) to 1 of 192 chromosomal segments using this panel. The regional mapping of new genes to cattle chromosomes can be rapidly achieved using this panel.

Involvement of 5-HT(2) receptor in imipramine-induced hyperglycemia in mice

Effects of imipramine on plasma glucose levels were investigated in mice. Imipramine i. p. induced dose-dependent hyperglycemia, which was enhanced by pretreatment with 5-HT (1/2/5/7) receptor antagonist methysergide and 5-HT (2A/2B/2C) receptor antagonist LY 53857. 5-HT (2C/2B) receptor antagonist SB 206553 also augmented imipramine-induced hyperglycemia although 5-HT (1A) and 5-HT (1B) receptor antagonist (-)-propranolol,5-HT (2A) receptor antagonist ketanserin and 5-HT (3/4) receptor antagonist tropisetron each had no effect. Imipramine i. p.-induced hyperglycemia was antagonized by the 5-HT (2C/2B) receptor agonist 1-(3-chlorophenyl)piperazine (mCPP), while the 5-HT (2B) receptor agonist BW 723C86 had no effect. Intracerebroventricular injection of imipramine also elevated plasma glucose levels, which is enhanced by SB 206553. Hyperglycemia elicited by central injection of imipramine was abolished by adrenalectomy. These results suggest that imipramine-induced hyperglycemia in mice is related to its inhibition of the central 5-HT (2C) receptor. Moreover, our results indicate that adrenaline release is related to imipramine-induced hyperglycemia.

Involvement of histamine H3 receptors in scratching behaviour in mast cell-deficient mice

BACKGROUND

Although the roles of histamine H3 receptors have been studied in several tissues such as the brain, lung, spleen, colon and peripheral sensory nerve endings, the involvement of H3 receptors in skin responses particularly in relation to scratching behaviour are not well documented.

OBJECTIVES

This work was performed to study the effects of histamine H3 antagonists on scratching behaviour in mast cell-deficient mice.

METHODS

Histamine H3 antagonists iodophenpropit and clobenpropit, histamine and substance P were injected intradermally into the rostral part of the back of mast cell-deficient (WBB6F1 W/Wv) and wild-type (WBB6F1+/+) mice and scratching behaviour was measured for 60 min. The effects of H1 antagonists on scratching behaviour induced by H3 antagonists were also investigated.

RESULTS

Intradermal injection of iodophenpropit and clobenpropit at doses of 10 and 100 nmol per site caused significant increases in scratching behaviour in both mast cell-deficient and wild-type mice. Histamine also caused a dose-related increase in the incidence of scratching behaviour, and a significant effect was observed at a dose of 100 nmol per site in both mast cell-deficient and wild-type mice. Substance P was also effective in causing scratching behaviour in both mast cell-deficient and wild-type mice. However, histamine H1 antagonists diphenhydramine and chlorphenamine failed to inhibit H3 antagonist-induced scratching behaviour in both types of mice.

CONCLUSIONS

Our results indicated that intradermal injection of H3 antagonists induces scratching behaviour and that chemical mediators other than histamine seem to be involved in the response.

Mapping of quantitative trait loci controlling trypanotolerance in a cross of tolerant West African N'Dama and susceptible East African Boran cattle

Trypanosomosis, or sleeping sickness, is a major disease constraint on livestock productivity in sub-Saharan Africa. To identify quantitative trait loci (QTL) controlling resistance to trypanosomosis in cattle, an experimental cross was made between trypanotolerant African N'Dama (Bos taurus) and trypanosusceptible improved Kenya Boran (Bos indicus) cattle. Sixteen phenotypic traits were defined describing anemia, body weight, and parasitemia. One hundred seventy-seven F2 animals and their parents and grandparents were genotyped at 477 molecular marker loci covering all 29 cattle autosomes. Total genome coverage was 82%. Putative QTL were mapped to 18 autosomes at a genomewise false discovery rate of <0.20. The results are consistent with a single QTL on 17 chromosomes and two QTL on BTA16. Individual QTL effects ranged from approximately 6% to 20% of the phenotypic variance of the trait. Excluding chromosomes with ambiguous or nontrypanotolerance effects, the allele for resistance to trypanosomosis originated from the N'Dama parent at nine QTL and from the Kenya Boran at five QTL, and at four QTL there is evidence of an overdominant mode of inheritance. These results suggest that selection for trypanotolerance within an F2 cross between N'Dama and Boran cattle could produce a synthetic breed with higher trypanotolerance levels than currently exist in the parental breeds.

Deletion of one of the duplicated Hsp70 genes causes hereditary myopathy of diaphragmatic muscles in Holstein-Friesian cattle

Heat-shock protein 70 (Hsp70) is a major chaperone that folds protein and prevents aggregation. The Hsp70 family contains both constitutive and stress-inducible forms. In humans, two of the inducible Hsp70 genes are located within the human major histocompatibility complex (MHC) on 6p21.3, as a duplicated locus, 12 kb apart from each other. We report that loss of one of the duplicated Hsp70 genes, the bovine homologue within the bovine MHC, is responsible for hereditary myopathy of diaphragmatic muscles (HMDM) in Holstein-Friesian cattle. Although the remaining Hsp70 gene is intact, Hsp70 protein levels are dramatically decreased in affected cattle. In normal diaphragmatic muscle, Hsp70 binds several proteins involved in energy metabolism including glycogen phosphorylase (PYGM). Immunohistochemical staining indicated that PYGM accumulated in the HMDM-specific core-like structures in affected cattle. Misfolding of energy-related proteins due to Hsp70 deficiency might lead to protein aggregation and muscle fibre degeneration.

Effects of [Arg8]-vasopressin on regional cerebral blood flow in spontaneously hypertensive rats

The effects of [Arg(8)]-vasopressin (AVP) and related compounds on regional cerebral blood flow (rCBF) in the hippocampus were studied using conscious spontaneously hypertensive rats (SHR). rCBF in the hippocampus decreased gradually with age in proportion to an increase in mean blood pressure. Subcutaneous injection of AVP caused a dose-dependent increase in rCBF in the hippocampus. The effects of the metabolic fragments AVP4-9 and AVP4-8 on rCBF were relatively weak. OPC-31260, a vasopressin V(2) antagonist, antagonized the AVP-induced increase in rCBF in the hippocampus. Furthermore, subcutaneous injection of DDAVP, a V(2) agonist, increased rCBF in the hippocampus. On the other hand, the AVP-induced increase in rCBF in the hippocampus was not antagonized by OPC-21268, a vasopressin V(1) antagonist. Intracerebroventricular injection of AVP caused no significant changes in rCBF in the hippocampus, even at a dose of 10 ng/site.

High-resolution genetic map of bovine chromosome 29 through focused marker development

Chromosome-specific libraries aid in the development of genetic maps and focus marker development in areas of the genome with identified quantitative trait loci (QTL). A small-insert BTA29 library constructed by microdissection of a 1:29 Rb-fusion cell line, was screened for dinucleotide repeats (CA)(15) and/or (GA)(15) with the goal of generating new genetic markers for this, the smallest bovine autosome. A total of 90 primer pairs were designed and 82 of these successfully amplified bovine genomic DNA by PCR. In addition to these 82 loci, primer pairs were developed for nine putative genes identified from the sequenced clones by BLAST searches of GenBank. A somatic cell panel was used to test for synteny of the new loci with two previously mapped BTA29 markers located on the MARC bovine linkage map. A total of 75 of the 82 microsatellite (ms) loci were integrated into the MARC bovine linkage map. Linkage analysis placed 69 ms markers on BTA29, five on BTAX and one on BTA1. Combined results of the somatic cell and linkage analyses place 79 new markers (ms and gene-related) on BTA29, six loci on BTAX and two loci on BTA1. The results of this effort significantly increase the marker density on BTA29, expanding the ability to fine map QTL associated with this chromosome.

Development of 47 new microsatellite markers from a BTA6 library

Chromosome-specific libraries provide a means to isolate genetic markers from specific chromosomal regions. A small-insert BTA6 library, constructed by microdissection, was screened for dinucleotide repeats (CA)15 and (GA)15. A total of 47 new microsatellite loci were developed and tested for polymorphism and informativeness using the MARC bovine mapping family.

A single nucleotide polymorphism of the low molecular mass polypeptide 7 gene influences the interferon response in patients with chronic hepatitis C

Transporter associated with antigen processing (TAP) and low molecular mass polypeptides (LMP) play crucial roles in the human leukocyte antigen (HLA) class I-restricted antigen presenting systems. This study was performed to elucidate whether these antigen-presenting gene polymorphisms could influence the response to interferon (IFN) treatment in patients with chronic hepatitis C. Polymorphisms of TAP and LMP genes in 175 hepatitis C virus (HCV) patients were determined by polymerase chain reaction-restriction fragment length polymorphism. The frequencies of these genes were compared between sustained-responders (n=49) and nonresponders (n=126), classified by biochemical and virological responses to IFN. The distributions of TAP1*, TAP2*, and LMP2 genes between sustained-responders and nonresponders did not differ. However, LMP7-K gene frequency in sustained-responders was higher than that in nonresponders [odds ratio 2.3 (95% confidence interval 1.1-4.6); 16%vs 7.9%]. Multivariate analysis revealed that LMP7-K and HCV-RNA quantity were independent factors influencing the outcome of IFN therapy [4.5 (1.4-14); P=0.011, 0.40 (0.24-0.65); P=0.0003, respectively]. Furthermore, among patients with a low viral load (< or = 2.0 Meq/mL), the LMP7-K positive patients had an even higher ratio of sustained response compared to those without LMP7-K [5.9 (1.6-22); 82%vs 44%; P=0.0062]. These findings suggest that a single nucleotide polymorphism of LMP7 gene is one of the important host factors which independently influence the response to IFN in patients with chronic hepatitis C.

High efficiency gene transfer to human CD34+ cells

We have previously reported the development of improved MLV-based retroviral vectors whose prototype is entitled MT (Kim et al, J. Virol. 72:994-1044; Yu et al, Gene Therapy 7:797-804). The MT vector does not contain any viral coding sequences, and thus the possibility of homologous recombination between the vector and the packaging genome is virtually nil. Indeed, in a shotgun RCR detection assay, an MT-based vector did not produce any RCR. On the contrary, the MFG vector, containing parts of all three viral coding sequences (gag, pol, and env), generated a significant number of RCR. In addition to being safe, MT-based vectors produce levels of gene expression and viral titer comparable to or higher than other vectors currently available within the community. Based on this vector, we have constructed a number of retroviral vectors that can be used for the treatment of a variety of human diseases. Our major target diseases are those that can be treated with or the status of which can be significantly improved with bone marrow transplantation. To obtain the most significant therapeutic effects, it is necessary to achieve the highest possible gene delivery efficiency, drive the highest level of gene expression, and prevent expression of the inserted therapeutic gene from being negatively influenced by the genome environment. To these ends, we compared various LTRs for their effects on the level of gene expression, tested the effect of cis-acting elements that may influence chromatin structure or position effect of the inserted gene, and studied different transduction conditions for their gene delivery efficiency. Data recently obtained from these experiments will be presented.

Changes in membrane potential induced by compound 48/80 in the peritoneal mast cells of rats

The changes in membrane potential induced by compound 48/80 were studied using rat peritoneal mast cells. The mean resting membrane potential of rat mast cells was -12.3 +/- 0.7 mM. When compound 48/80 was added to the mast cells, the cells were degranulated approximately 120 sec after the addition of the drug, after which immediate depolarization occurred. Degranulation of mast cells was not observed, even under the depolarization or hyperpolarization conditions caused by the replacement of a high K+ medium or the removal of K+ from the medium, respectively. Under both conditions, when compound 48/80 was added to the mast cells, degranulation was observed. Abrupt and marked depolarization was induced 30-60 sec after compound 48/80 was added. In addition, repolarization followed by gradual depolarization was observed without degranulation in mast cells treated with cytochalasin D after the addition of compound 48/80. These results suggest that the mast cells were depolarized by compound 48/80 independently of degranulation. It is also feasible that the gradual depolarization and repolarization induced by compound 48/80 in mast cells pretreated with cytochalasin D participated in the extracellular Na+ and Na+/K(+)-pump, respectively.

A new deletion mutation in bovine Claudin-16 (CL-16) deficiency and diagnosis

Bovine claudin-16/paracellin-1 (CL-16/PCLN-1) deficiency is an autosomal recessive disorder caused by a 37-kb deletion mutation containing the first four exons of the CL-16 gene, which leads to the absence of the CL-16 transcript (type-1 mutation). A PCR-based DNA test for the CL-16 mutation (type-1) was used to screen a herd of Wagyu cattle. A recent report suggested that affected cattle can be bred by dams diagnosed as normal, suggesting the presence of a new mutation in the CL-16 locus. We identified the new mutation as a 56-kb deletion containing exon-1 to -4 and 21-bp of exon-5 of CL-16, and refer to this as a type-2 mutation. A DNA test for specific for this mutation was then established.

Light-propagation characteristics of Y-branch defect waveguides in AlGaAs-based air-bridge-type two-dimensional photonic crystal slabs

Y-branch defect waveguides (DWGs) in an AlGaAs-based air-bridge-type two-dimensional (2D) photonic crystal (PC) slab were fabricated, and the resulting optical transmission spectra were measured. Optical beam propagation along the waveguide was successfully observed in vidicon IR images. The measured transmission spectra at the two output ports in the Y-branch DWG were remarkably similar in shape and magnitude. From comparison between the measured and calculated transmission spectra, the observed optical beam was identified as the guided mode based on the Y-branch DWG in the 2D PC slab. The results suggest that the Y-branch DWG used in the experiment has the potential to function as an ultrasmall 3-dB beam splitter with good performance.

Expression of apoptosis in placentae from mice lacking the prostaglandin F receptor

This study aimed to investigate the changes in apoptosis in the placenta and decidua of pregnant mice lacking the prostaglandin F receptor. Mouse placentae were removed from fetuses on days 10-23 of pregnancy. Apoptotic cells were examined by a DNA fragmentation assay and the terminal deoxynucleotidyl transferase-mediated dUDP nick end-labelling (TUNEL) technique. The placenta and decidual weight increased before day 18 and 14 of pregnancy, and then decreased with gestational day. After day 19, the fetuses gradually died in the uterus. All fetuses died in the uterus on day 23 of pregnancy. The number of apoptosis was not significantly different between wild type and FP-deficient mice before day 18 of pregnancy by DNA fragmentation and TUNEL staining. The DNA fragmentation was always more pronounced in decidual tissue on each day of pregnancy. DNA laddering on placentae was more extensive on day 22 than day 18. In placenta, most TUNEL-positive cells were detected in trophoblast and stromal cells. A higher intensity of apoptotic cells was in the decidual basalis. The main area was the centre of the decidual basalis, and was in decrease toward to margin of placenta. The index of TUNEL positive cells increased as gestation progressed toward termination. Especially, it was prominent in the placentae on day 22 compared with that day 18 of pregnancy. The increased TUNEL-positive staining in syncytiotrophoblast surface was found in placenta at post-term, compared with those at term. Apoptosis may provide insights into both normal placental development and placental dysfunction during an abnormal pregnancy from post-term pregnancy.