The SCID mouse mutant: definition, characterization, and potential uses

Mice homozygous for the scid mutation (scid mice) are severely deficient in functional B and T lymphocytes. The mutation appears to impair the recombination of antigen receptor genes and thereby causes an arrest in the early development of B and T lineage-committed cells; other hematopoietic cell types appear to develop and function normally. The arrest in lymphocyte development is not absolute; some young adult scid mice are "leaky" and generate a few clones of functional B and T cells. By 10-14 months of age, virtually all scid mice are leaky. Scid mice readily support normal lymphocyte differentiation and can be reconstituted with normal lymphocytes from other mice and even partially reconstituted with human lymphocytes. They also support the growth of allogeneic and xenogeneic tumors. Thus, scid mice are of interest for studies of both normal and abnormal lymphocyte development and function. In addition, they can be used to study the function of nonlymphoid cell types in the absence of lymphocytes.

Magnaporthe grisea pth11p is a novel plasma membrane protein that mediates appressorium differentiation in response to inductive substrate cues

Mutagenesis of Magnaporthe grisea strain 4091-5-8 led to the identification of PTH11, a pathogenicity gene predicted to encode a novel transmembrane protein. We localized a Pth11-green fluorescent protein fusion to the cell membrane and vacuoles. pth11 mutants of strain 4091-5-8 are nonpathogenic due to a defect in appressorium differentiation. This defect is reminiscent of wild-type strains on poorly inductive surfaces; conidia germinate and undergo early differentiation events, but appressorium maturation is impaired. Functional appressoria are formed by pth11 mutants at 10 to 15% of wild-type frequencies, suggesting that the protein encoded by PTH11 (Pth11p) is not required for appressorium morphogenesis but is involved in host surface recognition. We assayed Pth11p function in multiple M. grisea strains. These experiments indicated that Pth11p can activate appressorium differentiation in response to inductive surface cues and repress differentiation on poorly inductive surfaces and that multiple signaling pathways mediate differentiation. PTH11 genes from diverged M. grisea strains complemented the 4091-5-8 pth11 mutant, indicating functional conservation. Exogenous activation of cellular signaling suppressed pth11 defects. These findings suggest that Pth11p functions at the cell cortex as an upstream effector of appressorium differentiation in response to surface cues.

Identification, cloning, and characterization of PWL2, a gene for host species specificity in the rice blast fungus

Genetic analysis of host specificity in the rice blast fungus (Magnaporthe grisea) identified a single gene, PWL2 (for Pathogenicity toward Weeping Lovegrass), that exerts a major effect on the ability of this fungus to infect weeping lovegrass (Eragrostis curvula). The allele of the PWL2 gene conferring nonpathogenicity was genetically unstable, with the frequent appearance of spontaneous pathogenic mutants. PWL2 was cloned based on its map position. Large deletions detected in pathogenic mutants guided the gene cloning efforts. Transformants harboring the cloned PWL2 gene lost pathogenicity toward weeping lovegrass but remained fully pathogenic toward other host plants. Thus, the PWL2 host species specificity gene has properties analogous to classical avirulence genes, which function to prevent infection of certain cultivars of a particular host species. The PWL2 gene encodes a glycine-rich, hydrophilic protein (16 kD) with a putative secretion signal sequence. The pathogenic allele segregating in the mapping population, pwl2-2, differed from PWL2 by a single base pair substitution that resulted in a loss of function. The PWL2 locus is highly polymorphic among rice pathogens from diverse geographic locations.

Magnaporthe grisea pathogenicity genes obtained through insertional mutagenesis

We have initiated a mutational analysis of pathogenicity in the rice blast fungus, Magnaporthe grisea, in which hygromycin-resistant transformants, most generated by restriction enzyme-mediated integration (REMI), were screened for the ability to infect plants. A rapid primary infection assay facilitated screening of 5,538 transformants. Twenty-seven mutants were obtained that showed a reproducible pathogenicity defect, and 18 of these contained mutations that cosegregated with the hygromycin resistance marker. Analysis of eight mutants has resulted in the cloning of seven PTH genes that play a role in pathogenicity on barley, weeping lovegrass, and rice. Two independent mutants identified the same gene, PTH2, suggesting nonrandom insertion of the transforming DNA. These first 7 cloned PTH genes are described.

Evaluating the use of ram and suction during prey capture by cichlid fishes

We characterized prey-capture strategies in seven species of cichlid fishes representing diverse trophic habits and anticipated feeding abilities. The species examined were Petenia splendida, Cichla ocellaris, Cichlasoma minckleyi, Astronotus ocellatus, Crenicichla geayi, Heros severus (formerly Cichlasoma severum) and Cyprichromis leptosoma. Three individuals per species were filmed with video at 500Hz as they captured live adult Artemia sp. and Poecilia reticulata. For each feeding sequence, we measured the contribution of predator movement towards the prey (i.e. ram) and the movement of prey towards the predator due to suction. The use of ram differed significantly among prey types and predator species, varying as much as sixfold across predator species. High values of ram resulted in high attack velocities. Jaw protrusion contributed as much as 50% to overall ram values in some species, verifying its role in enhancing attack velocity. Suction distance did not vary significantly among species. Diversity in prey-capture behavior was therefore found to reflect differences among species in the strategy used to approach prey. Limited variation in the distance from which prey were sucked into the mouth is interpreted as the result of an expected exponential decline in water velocity with distance from the mouth of the suction-feeding predator. We propose that this relationship represents a major constraint on the distance over which suction feeding is effective for all aquatic-feeding predators.

T-lymphocyte development in scid mice is arrested shortly after the initiation of T-cell receptor delta gene recombination

Scid mice lack functional lymphocytes because they carry a mutation that impairs rearrangement of immunoglobulin and T-cell receptor (TCR) genes. Rearrangement of TCR delta, but not gamma and beta genes, was routinely observed in DNA of scid thymocytes and thymocyte hybridomas. TCR delta gene rearrangements appeared to involve D delta 1, D delta 2, and J delta 1 elements only; rearrangement of elements upstream of D delta 1 (e.g., V delta 1) was not observed, and transcripts corresponding to fully assembled TCR delta genes (VDJ delta or VDDJ delta) were not detected in RNA from scid thymocytes. These findings suggest that D delta 1, D delta 2, and J delta 1 may be among the first TCR gene elements to undergo recombination and that scid T-lineage cells are developmentally arrested during or shortly after this stage of differentiation. One class of TCR delta recombination fragments (D delta 2-J delta 1) was amplified by the polymerase chain reaction (PCR) and cloned, and the recombination junctions were sequenced. Most fragments showed normal coding joints. Interestingly, five of seven coding joints that lacked N insertions showed evidence of recombination between short stretches (2-3 bp) of homologous sequence. As discussed, the general absence of V delta-, J gamma-, and J beta-associated rearrangements, despite the occurrence of normal D delta 2-J delta 1 rearrangements, raises the possibility that the scid mutation may cause premature cessation of TCR gene recombination and thereby arrest early T-cell development.

Feeding with speed: prey capture evolution in cichilds

The diversity of both the locomotor and feeding systems in fish is extensive, although little is known about the integrated evolution of the two systems. Virtually, all fish swim to ingest prey and all open their buccal cavity during prey capture, but the relationship between these two ubiquitous components of fish feeding strikes is unknown. We predicted that there should be a positive correlation between ram speed (RS) and maximum gape (MG) because the accuracy of a predatory strike goes down with an increase in RS and fish with larger mouths eat larger, more evasive prey. For 18 species of neotropical cichlids, we used phylogenetic-independent contrasts to study the relationship between the predator closing speed (RS) and mouth size (MG) during prey capture. To provide a robust comparative framework, we augmented existing phylogenetic information available from the mitochondrial cytochrome b gene with sequences from the S7 nuclear ribosomal intron for these species. Then, we captured high-speed (500 images per second), lateral view feeding sequences of each species by using a digital video camera and measured both RS and MG. Uncorrected species values of MG and RS were positively and significantly correlated. When accounting for any of the set of phylogenetic relationships recovered, the independent contrasts of RS and MG remained significantly, and positively, correlated. This tight evolutionary coupling highlights what is likely a common relationship between locomotor behaviour and feeding kinematics in many organisms.

Detection and characterization of functional T cells in mice with severe combined immune deficiency

CD3+ alloresponsive T cell clones were derived from mice with severe combined immune deficiency (scid mice). T cell receptor beta and gamma gene rearrangements were analyzed to obtain insight into the nature and origin of these clones. We hypothesized that developing scid lymphocytes with an active, impaired recombinase system might generate functional lymphocytes by rare productive rearrangements at two critical antigen receptor loci. One alloresponsive clone showed evidence of both normally rearranged T cell receptor genes and genes with abnormal J region-associated deletions, supporting this hypothesis. Four additional alloresponsive clones, however, showed only conventional gene rearrangements. These data leave open the possibility that the recombinase activity, believed defective in scid mice, may be normalized in rare early B and T lymphoid cells or their precursors, to give rise to functional lymphocytes.

Creating smoke-free environments in recreational settings

To facilitate the banning of tobacco industry sponsorship, Australian health promotion foundations were established to provide health sponsorship to sport, arts, and racing organizations. Health sponsorship dollars procure health sponsorship benefits such as naming rights, signage, personal endorsement of a (health) product by a performer or player, and structural controls such as smoke-free policies. Data are presented from surveys and observations of spectators attending events sponsored by the West Australian Health Promotion Foundation (Healthway) and surveys of Healthway-sponsored organizations and the community. The results demonstrate that by using health sponsorship, Healthway increased the prevalence of smoke-free policies in recreational settings, and there was growing support for these policies. There was evidence of good compliance with smoke-free policies, thus reducing exposure to environmental tobacco smoke. The introduction of smoke-free policies in recreational settings has involved working collaboratively with sectors outside of health, taking an incremental approach to change, and gaining the support of stakeholders by communicating evaluation results.

T-cell receptor gene rearrangements in functional T-cell clones from severe combined immune deficient (scid) mice: reversion of the scid phenotype in individual lymphocyte progenitors

The severe combined immune deficient (scid) mouse mutant is characterized by a general absence of functional B and T lymphocytes. This deficiency appears to result from a defect in the variable-diversity-joining (VDJ) recombinase system, which is responsible for the assembly of V, D, and J gene segments that code for immunoglobulin and T-cell receptor (TCR) V regions. Most rearranged immunoglobulin or TCR genes in transformed scid lymphocytes contain abnormal J-associated deletions and are nonfunctional. A few functional lymphocyte clones do arise, however, in some young adult scid mice and in virtually all old scid mice; this phenomenon is referred to as leakiness. Alloreactive, CD3+ T-cell clones were isolated from leaky scid mice and the status of their TCR beta and gamma loci was examined in an effort to assess the nature of the recombinase activity that gives rise to functional scid lymphocytes. The recombination junctions of six gamma and two beta alleles were sequenced, representing four alloreactive T-cell clones. All of the junctions were indistinguishable from those seen in normal cells. These results cannot be attributed to selection by antigen because other rearranged TCR genes account for the TCR molecules expressed by these T-cell clones. We conclude that reversion of the scid phenotype can occur in rare lymphocyte progenitors and may account for most functional lymphocyte clones in leaky scid mice.

Selective detection of UCP 3 expression in skeletal muscle: effect of thyroid status and temperature acclimation

A novel peptide antibody to UCP 3 is characterized which is sensitive and discriminatory for UCP 3 over UCP 2, UCP 1 and other mitochondrial transporters. The peptide antibody detects UCP 3 expression in E. coli, COS cells and yeast expression systems. The peptide antibody detects a single approximately 33 kDa protein band in mitochondria from isolated rat skeletal muscle, mouse and rat brown adipose tissue, and in whole muscle groups (soleus and extensor digitorum longus) from mice. No 33 kDa band is detectable in isolated mitochondria from liver, heart, brain, kidney and lungs of rats, or gastrocnemius mitochondria from UCP 3 knock-out mice. From our data, we conclude that the peptide antibody is detecting UCP 3 in skeletal muscle, skeletal muscle mitochondria and brown adipose tissue mitochondria. It is also noteworthy that the peptide antibody can detect human, mouse and rat forms of UCP 3. Using the UCP 3 peptide antibody, we confirm and quantify the increased (2.8-fold) UCP 3 expression observed in skeletal muscle mitochondria isolated from 48-h-starved rats. We show that UCP 3 expression is increased (1.6-fold) in skeletal muscle of rats acclimated over 8 weeks to 8 degrees C and that UCP 3 expression is decreased (1.4-fold) in rats acclimated to 30 degrees C. Furthermore, UCP 3 expression is increased (2.3-fold) in skeletal muscle from hyperthyroid rats compared to euthyroid controls. In addition, we show that UCP 3 expression is only coincident with the mitochondrial fraction of skeletal muscle homogenates and not peroxisomal, nuclear or cytosolic and microsomal fractions.

Banning tobacco sponsorship: replacing tobacco with health messages and creating health-promoting environments

OBJECTIVE

To evaluate the replacement of Western Australian tobacco sponsorship with health promotion sponsorship by the Western Australian Health Promotion Foundation (known as "Healthway"), following the Tobacco Control Act 1990.

DESIGN

Process measures of performance were collected from 25 tobacco replacement projects (sponsorship by Healthway of sport, racing, and arts groups previously supported by tobacco companies) and 727 other health sponsorship projects, that is, new sponsorship provided by Healthway to these groups. Cross-sectional survey data were obtained from 917 respondents at tobacco replacement and 2352 at other sponsorship venues.

SETTING

Sport, racing, and arts venues sponsored by the Western Australian Health Promotion Foundation (Healthway) in 1991-95.

MAIN OUTCOME MEASURES

Population reach, occasions of media publicity, healthy structural changes, cognitive/attitudinal impact of health messages, and the prevalence of five health-risk behaviours.

RESULTS

Tobacco replacement and other sponsorship projects achieved comparable performance in publicity for health messages and in healthy structural change, but replacement projects achieved a fourfold higher level of direct population reach for a given amount of funding. Structural change towards a smoke-free environment occurred more often in tobacco replacement projects and a permanent smoke-free policy was achieved in 47% of projects, compared with 15% in other sponsorship projects. The prevalence ratio of current smoking at tobacco replacement venues was 1.86 (95% confidence interval 1.62 to 2.04) relative to other sponsorship venues. There was evidence of higher cognitive resistance to health messages at venues previously sponsored by tobacco companies.

CONCLUSIONS

A comprehensive ban on tobacco sponsorship linked to health promotion activities funded by tobacco tax delivers potential public health benefits that exceed those achieved by prohibition of tobacco sponsorship alone. Tobacco replacement venues offer opportunities for environmental modification, promotion of anti-smoking messages, and targeting groups that are hard to reach.

In vivo localization of cloned IL-2-dependent T cells

The quantitative organ distribution and tissue microenvironment positioning of radioisotopically labeled cloned T cells were characterized. Intravenous (iv) injection of 51chromium (51Cr)-labeled, long-term cultured cloned T-helper cells and cells from several cloned cytolytic T-lymphocyte lines (CTLL) resulted in poor localization of these cells in recipient lymphoid tissues, similar to results reported for activated lymphoblastoid cells. Simultaneous administration of interleukin 2 (IL-2) with labeled cells resulted in enhanced recovery from recipient spleen. By the intraperitoneal (ip) injection route, overall percentage recovery of injected radioactivity was lower than by the iv route, but significant localization to lymph nodes occurred. Examination of autoradiographs of tissue sections from recipients of [3H]adenosine-labeled cells showed most label associated with intact, isolated cells in the liver, lungs, spleen, and small intestine. By 24 hr after iv injection, labeled cells in spleen sections were distributed to both nonlymphoid and T- and B-lymphoid areas. These findings suggest that poor localization of these cells to recipient lymphoid tissue is due both to intrinsic characteristics of cultured lymphocytes and to the possible reduced viability of IL-2-dependent cells in vivo.

Time-resolved molecular dynamics of single and double hydrogen migration in ethanol

Being the lightest, most mobile atom that exists, hydrogen plays an important role in the chemistry of hydrocarbons, proteins and peptides and most biomolecules. Hydrogen can undergo transfer, exchange and migration processes, having considerable impact on the chemical behavior of these molecules. Although much has been learned about reaction dynamics involving one hydrogen atom, less is known about those processes where two or more hydrogen atoms participate. Here we show that single and double hydrogen migrations occurring in ethanol cations and dications take place within a few hundred fs to ps, using a 3D imaging and laser pump-probe technique. For double hydrogen migration, the hydrogens are not correlated, with the second hydrogen migration promoting the breakup of the C-O bond. The probability of double hydrogen migration is quite significant, suggesting that double hydrogen migration plays a more important role than generally assumed. The conclusions are supported by state-of-the-art molecular dynamics calculations.

Immunodetection of UCP1 in rat thymocytes

Thymi were dissected from rats and connective tissue was removed. Mitochondria were purified from isolated thymocytes and immunoblot analysis was performed using an antibody specific for uncoupling protein 1, which detected a 32.5 kDa protein associated with mitochondria from the thymocytes. This implies that rat thymocytes contain uncoupling protein 1.

Monoclonal antibodies to tissue-specific cell surface antigens. I. Characterization of an antibody to a prostate tissue antigen

Monoclonal antibodies were raised to PC-3 human prostate adenocarcinoma cells, and one hybridoma, designated F77-129, was extensively purified and used to characterize a PC-3 antigen. The F77-129 antibody also showed serological reactivity with the Du-145 prostate cancer line and with three of four breast carcinoma lines tested; it showed variable binding to a colon carcinoma line. Several other lines tested, including melanomas, fibrosarcomas, and leukemias, were completely negative. Immunoperoxidase staining of frozen surgical specimens showed binding to both normal and malignant prostate and breast tissue. Injection of radioiodinated F77-129 into tumor-bearing nude mice showed specific in vivo targeting to prostatic cancer implants. The antigen also showed surface modulation by bound antibody, suggesting possible clinical utility of this antibody in delivering immunotoxins to tumors.

Divergent physiological characteristics and responses to endurance training among inbred mouse strains

Both baseline values and adaptive changes in mice can vary depending on the genetic background. We aimed to assess variation in a battery of variables and their adaptations to endurance training in six inbred mouse strains. Males, n = 184, from A/J, BALB/cByJ, C3H/HeJ, C57BL/6J, DBA/2J, and PWD/PhJ strains were assigned to a control or an endurance group (5 weeks swimming exercise). Enzyme activity, histology of soleus (SOL) muscle, swimming endurance, cardiac ventricular and hind limb muscle weight, and femur length were examined. Endurance capacity, morphological and histological variables, and enzyme activity substantially differed among strains. For example, SOL weight was twofold higher and cross-sectional area (CSA) of fibers was ≈ 30% greater in C57BL/6J than in PWD/PhJ strain. The CSA of type 1 fibers were larger than type 2A in PWD/PhJ (P < 0.01); however, the reverse was true in DBA/2J and BALB/cByJ strains (P < 0.05). Swimming endurance in DBA/2J strain was ≈ 9 times better than in BALB/cByJ. Endurance training increased the activity of citrate synthase in gastrocnemius across strains (P < 0.01), however, changes in endurance were strain-specific; the C57BL/6J and DBA/2J strains improved substantially, whereas A/J and BALB/cByJ strains did not. In conclusion, genetic background is a potent determinant of the physiological characteristics and adaptations to training in mice.

Starvation-sensitive UCP 3 protein expression in thymus and spleen mitochondria

To date, UCP 3 has only been associated with skeletal muscle and brown adipose tissue (BAT). Using RT-PCR/PCR methodology, we show that human spleen and human thymus contain UCP 3. In addition, using peptide antibodies, previously demonstrated to be selective for UCP 3, we show that UCP 3 protein is present in mitochondria isolated from rat thymus and mitochondria isolated from reticulocytes, monocytes and lymphocytes of rat spleen. UCP 3 protein expression is also starvation-sensitive. UCP 3 abundance is augmented in mitochondria isolated from thymus and mitochondria isolated from lymphocytes of the spleen from fasted rats when compared to fed controls. The results are consistent with a role for UCP 3 in developing lymphocytes, thymus atrophy and fatty acid utilisation in spleen and thymus.

T cell leakiness in scid mice

FACS analysis showed that the incidence of leaky T cells increases with age, such that virtually all old scid mice (greater than 1 year) contain detectable CD3+ cells. The number of detectable T cells remained very low; individual old scid mice generally contained less than 10(5) CD3+ cells. When CD3+ populations in individual leaky mice were analyzed for expression of the T cell subset markers, CD4 and CD8, the ratios of CD4/CD8 were found to be markedly skewed relative to normal mice. This suggested the presence of very few T cell clones. Indeed, the analysis of TCR gene rearrangements in polyclonally stimulated T cell cultures revealed only 1-5 clones in the pooled spleen and lymph nodes of individual old scid mice. These studies also indicated that TCR gene rearrangements in the majority of the stimulated T cell cultures did not contain abnormal J-associated deletions that are characteristic of antigen receptor genes of scid lymphomas. Four of five alloreactive T cell clones from leaky scid mice also apparently lacked abnormal J-associated deletions in their rearranged TCR alleles. Therefore, most leaky lymphocytes appear to derive from progenitors with normal or near-normal scid recombinase activity. However, one of five leaky T cell clones (S1233) and one Con A stimulated monoclonal culture (8706) contained both normally and abnormally rearranged TCR genes. The configuration of TCR loci in such clones may reflect the ability of the defective scid recombinase to mediate normal rearrangements at a low frequency.

Warning: attending a sport, racing or arts venue may be beneficial to your health

Concerted efforts to create health-promoting sport, racing and arts venues have become possible since the advent of health promotion foundations in four of Australia's eight states and territories. Large numbers of Australians attend sport, racing and arts venues in pursuit of leisure activities. There is evidence that sport and racing participants and spectators, and certain subgroups of the arts community, have adverse risk-factor profiles that make them an ideal target for health promotion interventions. Through the use of sponsorship, health promotion foundations 'purchase' health-promoting policies in sport, racing and arts settings-policies that have the potential to become institutionalised once sponsorship dollars are depleted. This paper discusses the policies 'purchased' by the foundations and outlines a comprehensive surveillance and evaluation system developed for the Western Australian Health Promotion Foundation. The system monitors the implementation of health-promoting environments at the micro level (sponsorship project); intermediate level (sponsored group); and macro level (community). The article concludes by outlining some of the lessons learned in Western Australia. These provide the basis for development of best practice in working with sport, racing and arts groups, and other sectors outside health, to create health-promoting environments.

Evaluation of topical phenol as a means of producing autonomic denervation of the liver

Topical application of 90% phenol around the bile duct, portal vein, and hepatic artery, as well as along each of the three hepatic ligaments was tested for effectiveness of rapid and chronic denervation in cats. Because phenol produces nonselective nerve degeneration, it was assumed that proof of functional sympathectomy was adequate proof of disruption of parasympathetic and afferent nerves as well. Functional sympathetic neurons were evaluated by measuring physiological responses to direct electrical stimulation of the anterior hepatic plexus. Acute or rapid denervation was assessed by the degree of rise in portal blood pressure produced by nerve stimulation. Complete denervation appeared within 20 min and was still present by 80 min postapplication. Chronic denervation was tested by applying the phenol and recovering the cats for 6-14 days. An equal number (n = 6) of sham-denervated cats were compared. Phenol denervation did not alter basal glucose, insulin or glucagon levels, hematocrit, blood pressure, or hepatic glycogen levels. These variables are a good index of stress and metabolic status. Nerve stimulation in the chronic sham group raised portal pressure, arterial pressure, and blood glucose levels, whereas the chronic-denervated group showed no responses. The health of the two groups appeared normal with the sole difference being that the painted tissues were mildly discolored and more adhesions appeared in the phenol-denervated set. Thus phenol is a useful tool for producing hepatic denervation. It is less traumatic, faster, and more certain than surgical denervation. In addition, the hepatic lymphatics can be preserved using the topical application of phenol.

Characterization of interleukin 2 (IL-2)-dependent cytotoxic T-cell clones. V. Transfer of resistance to allografts and tumor grafts requires exogenous IL-2

The adoptive transfer of resistance to tumor grafts with cloned interleukin 2 (IL-2)-dependent cytotoxic T-cell lines was examined. Two clones were used: clone CTLL-A2 which recognizes H-2Dd determinants and clone CTLL-R5 which recognizes a unique cell surface antigen of BALB/c leukemia RL male 1. Systemic transfer of resistance with these clones was accomplished only when exogenous (rat or human) IL-2 was administered at the same time. Intraperitoneal injection of CTLL-A2 cells accelerated rejection of sarcoma Meth A (H-2Dd), but not ascites sarcoma BP8 (H-2k) or leukemia EL4 (H-2b) inoculated subcutaneously into C57BL/6 mice. CTLL-R5 cells were examined in local (Winn tests) as well as systemic transfer experiments. When mixed with leukemia cells before subcutaneous injection, they suppressed the growth of leukemia RL male 1 without exogenous IL-2. When injected intraperitoneally, CTLL-R5 cells inhibited the growth of subcutaneous grafts of leukemia RL male 1 only when exogenous IL-2 was administered at the same time. CTLL-R5 did not inhibit the growth of other radiation-induced BALB/c leukemias.

Fine-mapping of genes determining extrafusal fiber properties in murine soleus muscle

Muscle fiber cross-sectional area (CSA) and proportion of different fiber types are important determinants of muscle function and overall metabolism. Genetic variation plays a substantial role in phenotypic variation of these traits; however, the underlying genes remain poorly understood. This study aimed to map quantitative trait loci (QTL) affecting differences in soleus muscle fiber traits between the LG/J and SM/J mouse strains. Fiber number, CSA, and proportion of oxidative type I fibers were assessed in the soleus of 334 genotyped female and male mice of the F₃₄ generation of advanced intercross lines (AIL) derived from the LG/J and SM/J strains. To increase the QTL detection power, these data were combined with 94 soleus samples from the F₂ intercross of the same strains. Transcriptome of the soleus muscle of LG/J and SM/J females was analyzed by microarray. Genome-wide association analysis mapped four QTL (genome-wide P < 0.05) affecting the properties of muscle fibers to chromosome 2, 3, 4, and 11. A 1.5-LOD QTL support interval ranged between 2.36 and 4.67 Mb. On the basis of the genomic sequence information and functional and transcriptome data, we identified candidate genes for each of these QTL. The combination of analyses in F₂ and F₃₄ AIL populations with transcriptome and genomic sequence data in the parental strains is an effective strategy for refining QTL and nomination of the candidate genes.