Therapeutic and prophylactic uses of protein A in the control of Leishmania donovani infection in experimental animals

The role of the immunomodulator Protein A (PA) (from Staphylococcus aureus, Cowan I strain) in the control of leishmanial infection was studied in experimental animals. Treatment of Leishmania donovani infected hamsters with PA led to a moderate level of reduction of parasite load in their spleen (68%) and liver (46%). However, combination therapy of PA with the antileishmanial drug stibanate induced a more marked reduction of the spleen (88%) and liver (85%) parasitemia compared to that induced by PA or drug treatment alone. Similar results were also obtained with L. donovani infected BALB/c mice as the combination therapy of PA and stibanate led to a significant reduction (84%) of liver parasite load in comparison to that induced by PA (38%) or drug (61%) treatment alone. Apart from its therapeutic use, PA could also be used as a prophylactic agent in the control of leishmanial infection. Thus, treatment of hamsters with PA before leishmanial challenge significantly reduced their organ parasite load (by 59-78%) compared to that observed in infected controls without prior PA treatment. The antileishmanial effect of PA was likely to be mediated through the activation of macrophages leading to an enhancement of their phagocytic as well as leishmaniacidal activities. Subsequent studies demonstrated that PA treatment led to an increased production of nitric oxide by macrophages which could primarily be responsible for their enhanced parasite killing ability.

Functional analysis of a transrepressor domain in the hepatitis C virus core protein

Hepatitis C virus (HCV) is one of the major causative agents of chronic liver disease with the potential for development of hepatocellular carcinoma. The putative core protein of the virus has many intriguing properties, including transcriptional regulation of cellular and unrelated viral promoters. To further characterize the transregulatory function, a number of chimeric constructs were made by fusion of the core gene to the DNA binding domain of the yeast transactivator factor GAL4. The fusion protein exhibited a repressor activity on the herpes simplex virus thymidine kinase promoter via the upstream GAL4 DNA binding sites. A structure /function analysis of HCV core mutants in the context of the GAL4 DNA binding domain revealed that the transcriptional repressor activity was located near the N-terminus (amino acids 26 85). Transcription was strongly inhibited upon transfer of this repressor domain to a heterologous activation domain, (3CGln) of Epstein Barr virus transcription factor EBNA3C. Results from this study suggest that the HCV core protein contains an overall repressor activity, and that the repressor domain is located near the N-terminus.

Elderly patients with hypercholesterolaemia: a double-blind study of the efficacy, safety and tolerability of fluvastatin

BACKGROUND

Coronary heart disease is a major cause of morbidity and mortality in the elderly, a rapidly growing section of the population. Elderly patients have been excluded from most preventative risk factor trials.

METHODS

We evaluated fluvastatin, a fully synthetic hydroxymethyl glutaryl coenzyme A reductase inhibitor, in white patients older than 60 years, in seven hospital centres. After an 8-week cholesterol-decreasing diet phase, patients were allocated to groups to receive fluvastatin 40 mg daily (n = 33) or placebo (n = 36) given for 12 weeks. All patients had low-density lipoprotein cholesterol concentrations > or = 4.1 mmol/l 1 week before they were allocated to a treatment at random. After receiving randomised treatment for 12 weeks, 50 patients then received fluvastatin 40 mg daily on an open basis for a further 12 weeks.

RESULTS

Mean +/- SD age was 70.7 +/- 5.2 years for fluvastatin patients and 68.3 +/- 5.6 years for placebo. Mean +/- SD percentage changes in lipid concentrations from randomisation to the end of 12 weeks were calculated (n = 63) by intent-to-treat analysis. Total cholesterol decreased by 21.64 +/- 8.7% in the fluvastatin group and by 2.91 +/- 7.25% in the placebo group (P < 0.01); high-density lipoprotein cholesterol increased by 4.98 +/- 10.84% in the fluvastatin group and decreased by 0.05 +/- 8.68% in the placebo group (P = 0.05); low-density lipoprotein cholesterol decreased by 27.14 +/- 8.45% in the fluvastatin group and by 2.16 +/- 9.68% in the placebo group (P < 0.01); very-low-density lipoprotein cholesterol decreased by 30.70 +/- 30.65% in the fluvastatin group and by 9.80 +/- 28.6% in the placebo group (P < 0.01); triglyceride decreased by 18.13 +/- 17.35% in the fluvastatin group and by 2.97 +/- 21.85% in the placebo group (P < 0.01). There were no statistically significant differences between treatment groups for any other biochemical or haematological parameters. Adverse events were mainly mild, diminishing with continued treatment, and no event was serious by standard criteria. Patient-assessed tolerability after randomised treatment was 'very good' for 18 fluvastatin patients and for 26 placebo patients (P = 0.79). Seven patients withdrew from the 12-week follow-up (four from the fluvastatin group and three from the placebo group).

CONCLUSIONS

We conclude that fluvastatin decreases lipid concentrations effectively and safely in elderly patients, producing clinically significant decreases in total cholesterol, low-density lipoprotein cholesterol, triglyceride and, especially, very-low-density lipoprotein cholesterol, while increasing high-density lipoprotein cholesterol moderately.

Retrovirus receptor PiT-1 of the Felis catus

We isolated a cDNA encoding a feline homolog of human PiT-1, a sodium-dependent phosphate symporter which is utilized by gibbon ape leukemia virus (GALV) as a receptor for entry into host cells. The overall homology between the human and feline receptors is 92 and 93% at the nucleotide and deduced amino acid levels, respectively. Hydropathy analyses implied ten potential membrane spanning regions and, in analogy to human and murine homologs, five extracellular and four intracellular loops. Strikingly, the amino acid sequence of the fourth extracellular loop, which is critical for GALV surface glycoprotein binding, has complete identity between the human and feline PiT-1s, while the mouse PiT-1, non-functional for GALV entry, is quite divergent. Ectopic expression of the feline PiT-1 in guinea pig cells, which are non-permissive to feline leukemia virus (FeLV), subgroup B virus, conferred susceptibility to FeLV-B infection confirming the functional ability of the cloned product to serve as a receptor for a natural retrovirus of the homologous species.

Mechanism of protein A-induced amelioration of toxicity of anti-AIDS drug, zidovudine

Long-term treatment with 3-azido-3-deoxy thymidine (AZT) is often associated with myelosuppression. In AZT-treated Swiss mice, similar toxicological manifestations in terms of reduction of red blood and white blood cell counts and hemoglobin content had been observed as in AZT-treated AIDS patients. Pretreatment of animals with Protein A (PA) of Staphylococcus aureus Cowan I (1 microgram/ml), twice a week for two weeks, alleviated such hematopoietic toxicity due to AZT. AZT-induced reduction in colony-forming unit-erythroid (CFU-E) and colony-forming unit-granulocyte monocyte (CFU-GM) were also reversed by the combined treatment of AZT and PA. PA treatment showed an increased level of erythropoietin in the blood plasma, and cellularity of spleen, thymus, and bonemarrow was also increased in the group receiving combined treatment (PA+AZT), higher than that in the AZT group. AZT or its metabolites inhibited the activities of liver microsomal monooxygenases, which, however, could be regenerated in an accelerated manner by pretreatment of mice with PA. Moreover, the PA-treated group showed an accelerated clearance of AZT and/or its metabolites. These results suggest that such an immunopharmacologic approach might substantially reduce the toxic effects of drugs, such as AZT.

Clinicopathologic study of lupus nephritis

Needle biopsies of kidney were done in 35 cases of systemic lupus erythematosus (SLE) with renal lesions. The lupus nephritis were classified according to WHO classification and were correlated with response to therapy and prognosis. Detailed clinical features, routine haematological, biochemical tests (e.g., serum urea, creatinine, total protein and albumin, cholesterol, etc), examination of urine (degree of proteinuria and cells) and occurrence of various auto-antibodies e.g., antinuclear antibody (ANA), anti double stranded DNA (anti DsDNA) by enzyme immunoassay (EIA) method, LE cells and rheumatoid factor (RF) were studied in all cases. Clinically hypertension was present in 19 (54.3%) cases and nephrotic range of proteinuria was detected in 20 (57.2%) cases. ANA was found in 31 (88.5%) cases, anti DsDNA 24 (68.5%) and LE cells were detected in 25 (71.5%) cases. RF was detected in 2 (5.7%) cases. Histologically the most frequent lesions were class IV occurring in 15 cases (42.8%) with initial complete remission achieved only 4 cases by immunosuppressive therapy. Active lesions were also most frequent in this class. Class III lesions were found in 8 (22.8%) cases with 6 cases had complete remission. The best prognosis was noted in class II cases with 4 out of 5 (14.3%) cases had complete remission. Class V lesions were found in 6 (17.2%) cases with complete remission achieved in 3 cases. Only one patient presented with class VI lesion. RF positive cases had milder renal lesions.

Structure based design: novel spirocyclic ethers as nonpeptidal P2-ligands for HIV protease inhibitors

A series of novel spirocyclic ethers were designed to function as nonpeptidal P2-ligands for HIV-1 protease inhibitors. Incorporation of designed ligands in the (R)-(hydroxyethylamino)sulfonamide isostere afforded potent HIV protease inhibitors.

Potent HIV protease inhibitors incorporating high-affinity P2-ligands and (R)-(hydroxyethylamino)sulfonamide isostere

Design and synthesis of a series of very potent nonpeptide HIV protease inhibitors are described. The inhibitors are derived from novel high affinity P2-ligands and (R)-(hydroxyethylamino)sulfonamide isostere.

Correlation between stationary phase survival and acid trehalase activity in yeast

The levels of two trehalose hydrolysing enzymes, acid trehalase (AT) and neutral trehalase (NT), have been investigated in Candida utilis at different stages of growth; in complete contrast to Saccharomyces cerevisiae, significant AT activity appears to be absent at all stages of growth studied in C. utilis. In addition, presence of only very low amounts of iso-aspartyl methyl transferase (IMT) activity at the onset of stationary phase and lower survival ability in early stationary phase in contrast to that of S. cerevisiae lend support to the ideas that (a) lower degree of survival of C. utilis in the stationary phase may be a direct consequence of inability to mobilise stored trehalose due to absence of intracellular AT and reduced levels of IMT activities and (b) trehalose may have a dual role vis-à-vis stress resistance in yeasts.

Regulation of acid trehalase activity by association-dissociation in Saccharomyces cerevisiae

Acid trehalase (AT) has always been reported to be copurified with invertase (I) and a 40 kDa additional protein. Glucose grown stationary phase cells of Saccharomyces cerevisiae contained least I activity. So, it was attempted to purify AT from these cells (I:AT = 10.83). Studies on specific activity, percent recovery and I:AT ratio of different pools, collected during purification of AT, indicated that samples containing ratio I:AT < 2.2 were unstable. Purification methodology favouring association (DEAE-Sephadex chromatography) resulted in gaining total activity while methodology favouring dissociation (HPGPLC) resulted in tremendous loss in recovery. Active pool (Pool 1X) appeared to be electrophoretically homogeneous but dissociated into 175, 90, 68, 61, 57 (minor bands) and 37-41 (major band) molar mass (kDa) bands on SDS-PAGE. Inactive pools (Pools 1Y, 3X, 3Y) did not contain the 37-41 kDa major band. So, association of both I and a 37-41 kDa protein with AT appeared to be essential. Two bands of isoelectric pH (pI) 4.6 and 4.7 were present in pool 1X enzyme preparation. All SDS-PAGE-resolved bands of pool 1X, in an average, contained high aspartate/asparagine and low cysteine residues. AT activity appeared to be highly sensitive to the change in pH and also to agents affecting ionisation of protein, e.g., betaine, NaCl, acetate, etc. Association of AT components in presence of NaCl was demonstrated spectrophotometrically. Specific activity of AT decreased with dilution. Substrate mediated allosterism for this enzyme preparation suggested that AT existed as an equilibrium mixture of protomer-oligomer. It was suggested that reversible association-dissociation was a mechanism for the regulation of AT activity.

Autoantigen Ku and its role in multiple cellular processes

Ku is a DNA binding protein composed of 70 and 80 kDa subunits which was discovered as autoantigen in a patient with scleroderma-polymyositis overlap syndrome. Ku can bind to the end of DNA and also to some internal sequences. Ku-autoantigen acts as a potential transcription factor for several RNA polymerase II genes and RNA polymerase I gene. Ku is also associated with DNA-dependent protein kinase and involved in V(D)J recombination and DNA break repair mechanisms. Ku may be involved in replication, helicase activity and cell signaling. Therefore, Ku-autoantigen is a very important cellular factor which plays important role in the multiple cellular processes.

Modulation of tryptophan environment in membrane-bound melittin by negatively charged phospholipids: implications in membrane organization and function

Melittin is a cationic hemolytic peptide isolated from the European honey bee, Apis mellifera. Since the association of the peptide in the membrane is linked with its physiological effects, a detailed understanding of the interaction of melittin with membranes is crucial. We have investigated the interaction of melittin with membranes of varying surface charge in the context of recent studies which show that the presence of negatively charged lipids in the membrane inhibits membrane lysis by melittin. The sole tryptophan residue in melittin has previously been shown to be critical for its hemolytic activity. The organization and dynamics of the tryptophan residue thus become important to understand the peptide activity in membranes of different charge types. Wavelength-selective fluorescence was utilized to monitor the tryptophan environment of membrane-bound melittin. Melittin exhibits a red edge excitation shift (REES) of 5 nm when bound to zwitterionic membranes while in negatively charged membranes, the magnitude of REES is reduced to 2-3 nm. Further, wavelength dependence of fluorescence polarization and near-UV circular dichroism spectra reveal characteristic differences in the tryptophan environment for melittin bound to zwitterionic and anionic membranes. These studies are supported by time-resolved fluorescence measurements of membrane-bound melittin. Tryptophan penetration depths for melittin bound to zwitterionic and anionic membranes were analyzed by the parallax method [Chattopadhyay, A., and London, E. (1987) Biochemistry 26, 39-45] utilizing differential fluorescence quenching obtained with phospholipids spin-labeled at two different depths. Our results provide further insight into molecular details of membrane lysis by melittin and the modulation of lytic activity by negatively charged lipids.

Describing functions for nonlinear optical systems

The concept of describing functions is useful for analyzing and designing nonlinear systems. A proposal for using the idea of describing functions for studying the behavior of a nonlinear optical processing system is given. The describing function can be used in the same way that a coherent transfer function or optical transfer function is used to characterize linear, shift-invariant optical processors. Two coherent optical systems for measuring the magnitude of the describing function of nonlinear optical processors are suggested.

Alignment considerations in extrinsic fiber-optic sensors

The performance of a fiber-optic sensor and its overall cost depend on the packaging of the sensor. Alignment of different optical, optoelectronic, and mechanical components is a key problem in the package design of a fiber-optic sensor. An intensity based fiber-optic sensor that can be used as a refractive-index or displacement sensor is considered as a case study in analyzing the effects of alignment on the performance of a fiber-optic sensor. Alignability of this sensor package is defined and calculated, taking into account the coupling efficiency and effects of various misalignments. Guidelines for making the package so that the fiber-optic sensor works more efficiently are developed from our calculations.

Adenosine A2 receptors modulate haloperidol-induced catalepsy in rats

The effect of adenosine A1 and A2 receptor agonists and antagonists was investigated on haloperidol-induced catalepsy in rats. Pretreatment (i.p.) with the non-selective adenosine receptor antagonist, theophylline, or the selective adenosine A2 receptor antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX), significantly reversed haloperidol-induced catalepsy, whereas the selective adenosine A1 receptor antagonists, 8-phenyltheophylline and 8-cyclopentyl-1,3-dipropylxanthine produced no effect. Similar administration of the adenosine A2 receptor agonists, 5'-(N-cyclopropyl)-carboxamidoadenosine and 5'-N-ethylcarboxamidoadenosine (NECA), and the mixed agonists with predominantly A1 site of action, N6-(2-phenylisopropyl) adenosine or 2-chloroadenosine, potentiated haloperidol-induced catalepsy. Higher doses of the adenosine agonists produced catalepsy when given alone. However, N6-cyclopentyladenosine, a highly selective adenosine A1 receptor agonist, was ineffective in these respects. The per se cataleptic effect of adenosine agonists was blocked by DMPX and the centrally acting anticholinergic agent, scopolamine. Scopolamine also attenuated the potentiation of haloperidol-induced catalepsy by adenosine agonists. Further, i.c.v. administration of NECA and DMPX produced a similar effect as that produced after their systemic administration. These findings demonstrate the differential influence of adenosine A1 and A2 receptors on haloperidol-induced catalepsy and support the hypothesis that the functional interaction between adenosine and dopamine mechanisms might occur through adenosine A2 receptors at the level of cholinergic neurons. The results suggest that adenosine A2, but not A1, receptor antagonists may be of potential use in the treatment of Parkinson's disease.

Possible role of isoaspartyl methyltransferase towards regulation of acid trehalase activity in Saccharomyces cerevisiae

Logarithmically growing cells of S. cerevisiae contained high neutral trehalase (NT) activity while stationary-phase cells had high acid trehalase (AT) activity. Change in activity profile of AT and NT were different during growth under different conditions, particularly during growth in acetate medium and up to 1 h of germination period, but that for AT and isoaspartyl methyltransferase (IMT) were found to be almost identical. Concomitant increase in NT activity as well as increase in cAMP level was noticed at the onset of spore germination. Increase in AT and IMT activities as well as decrease in S-adenosyl-L-methionine (AdoMet) level were noticed during stationary phase of growth. Acidic polyacrylamide gel electrophoresis and subsequent autoradiography revealed that substrate of IMT was a protein of molar mass around 82 kDa which could be an AT. Methylated AT was found to be more active while non-methylated AT was relatively less active in comparison to the untreated sample. Since AT existed as an equilibrium mixture of protomer and oligomer, it was suggested that IMT catalysed carboxyl methylation might have some contribution towards the regulation of AT activity.

Characterisation of a xylanolytic amyloglucosidase of Termitomyces clypeatus

A xylanolytic amyloglucosidase of Termitomyces clypeatus was characterised with respect to other amyloglucosidases. The enzyme contained high alpha-helix destabilising amino acids but no sulphur amino acid. It contained high threonine and serine, analogous to other raw starch hydrolysing enzymes. Both xylanase and amyloglucosidase activities were gradually lost with the progress of tryptophan oxidation by NBS and total inactivation occurred after oxidation of 4-5 tryptophan residues. In the presence of substrates (either starch or xylan), complete inactivation of either activities was not noticed even after oxidation of 7.7 mol of tryptophan residues. Inactivation by HNBB was not possible in the absence of any denaturant. Only 4.9 mol of tryptophan could be modified in the presence of 5 M urea which resulted in only 42% inhibition of activity. Thus modified enzyme had higher Vm/Km and lower pH optima in comparison to those of native enzyme. It was suggested that tryptophan was present at the substrate binding site and not at the active site. No such change in activity was noticed after modification of tyrosine, lysine or arginine residues. HPGPLC analysis of both dilute and concentrated enzyme solution indicated that the enzyme existed as an equilibrium mixture of protomer-oligomer. Perhaps for this reason molar mass of NAI modified enzyme appeared to be almost half of that modified by NAI in presence of substrate. Arrhenius plot of the enzyme also indicated reversible oligomerisation as a function of temperature.

The dual role of helix-loop--helix-zipper protein USF in ribosomal RNA gene transcription in vivo

We have previously demonstrated that the core promoter of rat ribosomal RNA gene (rDNA) contains an E-box-like sequence to which the core promoter binding factor CPBF binds and that the 44 kDa subunit of this protein is immunologically related to USF1, the helix--loop--helix-zipper DNA binding protein. Further, we showed that RNA polymerase I (pol I) transcription in vitro is competed by oligonucleotides containing USF-binding site, which suggested a key role for USF in rDNA transcription. To prove the potential role of USF in pol I transcription in vivo, USF1 and USF2 homodimers and USF1/USF2 heterodimer were overexpressed in CHO cells by transfection of the respective cDNAs. Co-transfection of a plasmid containing rDNA followed by primer extension analysis showed that overexpression of USF1 and USF2 as homodimers resulted in inhibition of rDNA transcription by as much as 85-90% whereas overexpression of USF1/USF2 in the heterodimeric form activated transcription approximately 3.5-fold. Transfection of mutant USF2 cDNA that is devoid of the basic DNA-binding domain produced only minimal inhibition of rDNA transcription. These data show that USF can modulate transcription of rRNA gene in vivo by functioning as a repressor (homodimer) or activator (heterodimer) of pol I transcription in vivo and suggest that inhibition of rDNA transcription may be responsible for the antiproliferative action of USF homodimers.

Optimum and sub-optimal temperature effects on stomata and photosynthesis rate of determinate soybeans

Stomatal frequency, length and width were studied in two determinate type soybean (Glycine max L. Merr.) cultivars at 15, 20 and 25 degrees C on 60th day after emergence. The stomatal frequency on the adaxial leaf surface did not show any consistent trend for the increase of growing temperatures but on the abaxial surface, stomatal frequency significantly decreased for every increase of 5 degrees C. Akishirome had 503, 454 and 379 stomata mm-2 and Akiyoshi had 471, 442 and 384 mm-2 at 15, 20 and 25 degrees C respectively. The stomatal lengths of both surfaces increased toward optimum temperature and were longer in the adaxial surface Maintaining this trend, the lengths varied between 16.3 to 23.4 micrometers on the adaxial surface and from 14.2 to 21.5 micrometers on the abaxial surface. Width of the whole stomatal apparatus at noon time did not show any significant variation due to environmental temperature. Net photosynthesis rate of 4th leaf from top significantly increased in higher temperatures in both cultivars and showed similar trend at 32nd day after emergence and on 62nd day after emergence. Stomatal conductance increased and dark respiration decreased with increasing temperature. Plants grown in 25 degrees C were transferred to 15, 20 and 30 degrees C temperature chambers. On the 30th day after emergence, 4 hours of treatment resulted similar significant effects on net photosynthesis (ranging between 12.55 and 31.37 micromoles CO2 m-2 s-1 in Akishirome, and between 16.26 to 34.53 micrometers CO2 m-2 s-1 in Akiyoshi). 72 hours of similar treatments at 60 day after emergence also produced identical results. Therefore, higher temperature increased stomatal size but decreased its frequency, and increased net photosynthesis and stomatal conductance.

Subpopulations of T lymphocytes in the peripheral blood and lymph nodes of Indian kala-azar patients

Distribution of T cells in the peripheral blood and lymph nodes of Indian kala-azar (KA) patients was studied by using appropriate phenotypic markers for CD2+, CD4+ and CD8+ cells. Significant reduction in the CD2+, CD4+ cell numbers as well as CD4+/CD8+ cell ratio was noted in the peripheral blood of active KA cases. Such alteration in the T cell population appeared to be a manifestation of the disease process as it showed a tendency to return close to normalcy several months after successful chemotherapy. Histopathological studies of KA patients with lymphadenopathy demonstrated gradual destruction of lymph node follicular architecture which correlated well with the severity and duration of illness. Massive infiltration of CD2+ cells in the cortical region of lymph node was evident. The observed preponderance of CD4+ cells over CD8+ ones in these infiltrates was in sharp contrast to the distribution pattern of these cells in the periphery. Significance of these findings is discussed in relation to the current concepts on the immunology of leishmaniasis and related diseases.

Molecular cloning and characterization of human FGF8 alternative messenger RNA forms

Three alternatively spliced mRNA isoforms of the human fibroblast growth factor-8 (FGF8) gene, expressed in a prostatic carcinoma cell line, have been isolated as cDNA clones and characterized by DNA sequencing. The clones, designated FGF8a, FGF8b, and FGF8e, differ from each other at the NH2-terminal region of the mature proteins and share extensive nucleotide sequence homology in the protein coding region to the corresponding mouse cDNA isoforms that were previously reported. FGF8a and FGF8b exhibit identical amino acid sequences to those of their murine counterparts. FGF8e displays partial sequence variation from the corresponding mouse clone only in the extra exon sequence found in this isoform in both species. There is extensive sequence diversity between FGF8 (human) and Fgf8 (murine) genes in the 3'-untranslated region of the mRNAs. Northern blot analyses revealed FGF8 mRNA expression only in fetal kidney tissue among the various fetal and adult human tissues tested. The reverse transcription-PCR amplification method, however, detected FGF8 mRNA expression in adult prostate, kidney, and testes (the tissues that were tested) and in all normal and tumor prostatic epithelial cell lines examined; although expression of both FGF8a and FGF8b was seen in kidney and testes, FGF8b appeared to be the predominantly expressed species in the prostatic tissue and cell lines analyzed by reverse transcription-PCR. To address the biological effect of specific isoform expression, NIH3T3 cells were transfected with a eukaryotic expression vector containing cDNA for FGF8a, FGF8b, or FGF8e. Consistent with previous reports on differences in the transforming potential of mouse FGF8 isoforms, human FGF8b was found to induce marked morphological transformation to NIH3T3 cells and strong tumorigenicity of the transfected cells in nude mice. Human FGF8a and FGF8e were moderately transforming in NIH3T3 cells, and the transfected cells were moderately tumorigenic in vivo. These results document the production of three alternatively spliced FGF8 mRNAs in human tissues and the transforming and tumorigenic potential of their protein products. Moreover, these data, combined with the tissue-specific expression of these isoforms, suggest that they may have different biological functions.