11C-methionine PET aids localization of microprolactinomas in patients with intolerance or resistance to dopamine agonist therapy.

PURPOSE: To assess the potential for 11C-methionine PET (Met-PET) coregistered with volumetric magnetic resonance imaging (Met-PET/MRCR) to inform clinical decision making in patients with poorly visualized or occult microprolactinomas and dopamine agonist intolerance or resistance. PATIENTS AND METHODS: Thirteen patients with pituitary microprolactinomas, and who were intolerant (n = 11) or resistant (n = 2) to dopamine agonist therapy, were referred to our specialist pituitary centre for Met-PET/MRCR between 2016 and 2020. All patients had persistent hyperprolactinemia and were being considered for surgical intervention, but standard clinical MRI had shown either no visible adenoma or equivocal appearances. RESULTS: In all 13 patients Met-PET/MRCR demonstrated a single focus of avid tracer uptake. This was localized either to the right or left side of the sella in 12 subjects. In one patient, who had previously undergone surgery for a left-sided adenoma, recurrent tumor was unexpectedly identified in the left cavernous sinus. Five patients underwent endoscopic transsphenoidal selective adenomectomy, with subsequent complete remission of hyperprolactinaemia and normalization of other pituitary function; three patients are awaiting surgery. In the patient with inoperable cavernous sinus disease PET-guided stereotactic radiosurgery (SRS) was performed with subsequent near-normalization of serum prolactin. Two patients elected for a further trial of medical therapy, while two declined surgery or radiotherapy and chose to remain off medical treatment. CONCLUSIONS: In patients with dopamine agonist intolerance or resistance, and indeterminate pituitary MRI, molecular (functional) imaging with Met-PET/MRCR can allow precise localization of a microprolactinoma to facilitate selective surgical adenomectomy or SRS.

TAF10 and TAF10b partially redundant roles during Drosophila melanogaster morphogenesis.

Transcription of eukaryotic genes requires the cooperative action of the RNA polymerase complex, the general transcription factors (TFIIB, TFIID, TFIIE, TFIIF and TFIIH) and chromatin modifiers. The TFIID complex contributes to transcriptional activation by several mechanisms and has a subunit with associated histone acetyltransferase (HAT) activity. The histone modifier SAGA complex has both HAT and deubiquitylase (DUB) activities. TFIID and SAGA share several TBP-associated factors (TAFs), but not their HAT subunit. Recently, several duplicated TAF proteins have been identified in higher eukaryotes, but their functional diversity has been so far poorly characterized. Here, we report the functional similarities and differences of TAF10 and TAF10b, the two TAF10 orthologs of Drosophila melanogaster. Results from in silico modeling suggest that dTAF10 and dTAF10b have similar secondary structures characterized by the presence of a histone-fold domain. Additionally, dTAF10 and dTAF10b share interaction partners and show similar expression patterns in neuronal tissues. Nonetheless, dTAF10 and dTAF10b seem to have partly distinct functions. To investigate their roles, we generated dTaf10-dTaf10b double-mutants and rescued the mutant flies with transgenes, which allowed the translation of either dTAF10 or dTAF10b protein. We found that the loss of dTAF10b resulted in pupal lethality, while animals lacking dTAF10 were able to form puparium. dTaf10 mutant adults showed distorted eye morphology. During DNA repair, dTAF10 and dTAF10b act redundantly, suggesting that these proteins have distinct but partially overlapping functions.

In vivo effects of abolishing the single canonical sumoylation site in the C-terminal region of Drosophila p53.

Using yeast two-hybrid screens we determined that Drosophila (Dm)p53 interacts with proteins involved in sumoylation (UBA2, UBC9 and PIAS) through different regions of its C-terminal domain. A K302R point mutation within a single canonical sumoylation site of Dmp53 did not abolish the observed interactions. These observations prompted us to analyze whether Dmp53 sumoylation at this site has any functional role in vivo. Genetic assays showed that deleting one copy of genes involved in sumoylation (lwr, Su(var)2-10 or smt3 heterozygosity) enhanced slightly the mutator phenotype of Dmp53. We compared the in vivo effects of wild type and K302R Dmp53 overproduced from transgenes and determined that similar levels of expression of the mutant and wild type proteins resulted in similar phenotype, and the two proteins showed similar cellular localization. The half life and the trans-activator activity of K302R mutant and wild type Dmp53 were also comparable. Lastly, by analyzing wild type and K302R Dmp53 expressed at different levels in animals and in S2 cells we detected no differences between the mobility of the mutant and wild-type protein. From these data we conclude that under normal developmental conditions the loss of SUMO modification at K302 does not affect Dmp53 function significantly.

Genes of the ecdysone biosynthesis pathway are regulated by the dATAC histone acetyltransferase complex in Drosophila.

Uncovering mechanisms that regulate ecdysone production is an important step toward understanding the regulation of insect metamorphosis and processes in steroid-related pathologies. We report here the transcriptome analysis of Drosophila melanogaster dAda2a and dAda3 mutants, in which subunits of the ATAC acetyltransferase complex are affected. In agreement with the fact that these mutations lead to lethality at the start of metamorphosis, both the ecdysone levels and the ecdysone receptor binding to polytene chromosomes are reduced in these flies. The cytochrome genes (spookier, phantom, disembodied, and shadow) involved in steroid conversion in the ring gland are downregulated, while the gene shade, which is involved in converting ecdysone into its active form in the periphery, is upregulated in these dATAC subunit mutants. Moreover, driven expression of dAda3 at the site of ecdysone synthesis partially rescues dAda3 mutants. Mutants of dAda2b, a subunit of the dSAGA histone acetyltransferase complex, do not share phenotype characteristics and RNA profile alterations with dAda2a mutants, indicating that the ecdysone biosynthesis genes are regulated by dATAC, but not by dSAGA. Thus, we provide one of the first examples of the coordinated regulation of a functionally linked set of genes by the metazoan-specific ATAC complex.

Misregulated RNA Pol II C-terminal domain phosphorylation results in apoptosis.

Misregulation of the level of RNA polymerase II carboxyl-terminal domain (CTD) phosphatase, Fcp1, in Drosophila results in high level of caspase-mediated apoptosis. Apoptosis induction by Fcp1 misregulation requires the presence of Drosophila melanogaster (Dm)p53, but occurs without the transcriptional activation of Dmp53 proapoptotic targets rpr, ark, and hid. Overproduction of a transcription activation-defective mutant Dmp53 protein increases, while Dmp53 null background decreases significantly the level of apoptosis in Fcp1-misregulated animals. Generating the apoptotic signal does not require the function of the ATM and Rad3-related kinase (ATR), and no significant level of nucleo-cytoplasmic translocation of Dmp53 is detectable in cells expressing Fcp1 at an abnormal level. Immunostaining of larval salivary gland polytene chromosomes with anti-Dmp53 antibodies indicates Dmp53 localization at several transcriptionally active chromosomal regions in wild-type cells, while in Fcp-misregulated cells the association of Dmp53 with specific chromosomal sites is decreased.

Different sets of genes are activated by p53 upon UV or ionizing radiation in Drosophila melanogaster.

The p53 tumour suppressor plays central role in the maintenance of genome integrity. P53 deficient fruit flies are highly sensitive to ionizing radiation (IR) and show genome instability suggesting that the Drosophila melanogaster p53 (Dmp53) is necessary for the proper damage response upon IR. We found that Dmp53 null fruit flies are highly sensitive to ultraviolet radiation (UV) as well. We analyzed the expression levels of apoptotic genes in wild type and Dmp53 null mutant animals after UV or IR using quantitative real-time RT-PCR. Ark (Apaf-1 related killer) was induced in a Dmp53-dependent way upon UV treatment but not by IR, hid (head involution defective/wrinkled) was induced upon both types of DNA damage, while reaper was induced only upon IR but not UV treatment. Using microarray analysis we identified several further genes that are activated upon UV irradiation in the presence of wild type Dmp53 only. Some but not all of these genes show Dmp53-dependent activation upon IR treatment as well. These results suggest that Dmp53 activates distinct cellular pathways through regulation of different target genes after different types of DNA damage.

Evaluation of palatal saliva flow rate and oral manifestations in patients with Sjögren's syndrome.

OBJECTIVE: The purpose of this study was to describe the oral properties of Sjögren's syndrome (SS), including the determination of palatal saliva (PS) flow rate. SUBJECTS AND METHODS: Forty-nine SS patients and 43 healthy controls participated. Subjective symptoms were recorded and clinical assessments of the oral mucosal, dental and periodontal status were made. Unstimulated whole saliva (WS) and PS flow rates, the number of decayed, missing and filled teeth (DMF-T number), the gingival bleeding index (GBI) and the periodontal probing depth (PPD) were determined. RESULTS: Despite the decrease in the flow rate of WS in SS patients, PS was not different from those of the controls (1.57 +/- 1.02 and 1.35 +/- 2.5 microl cm(-2) min(-1), respectively). GBI (20.0% vs. 10.5%, respectively), DMF-T (27.1 +/- 6.12 vs. 23.0 +/- 6.99, respectively) and PPD (2.28 +/- 1.09 mm vs. 1.82 +/- 0.73 mm, respectively) were higher in SS compared with the controls (P < 0.05). DMF-T and PPD showed a positive correlation with anti-SSA and/or anti-SSB antibody positivity in the serum (P < 0.05). CONCLUSIONS: Data of the present study suggest that the subjective feeling of xerostomia in SS patients is the result of a decrease in the volume of the whole saliva, and not of the viscous PS. Correlation of DMF-T and PPD with autoantibody positivity reveals that the oral health status of SS patients may be associated with the general autoimmune process.

Induction of heat shock proteins fails to produce protection against trypsin-induced acute pancreatitis in rats.

Heat shock proteins (HSPs) are necessary in the synthesis, degradation, folding, transport, and translocation of different proteins. It is well known that the increased expression of HSPs may have a protective effect against cerulein-induced pancreatitis in rats or against choline-deficient ethionine-supplemented diet model pancreatitis in mice. The aim of this study was to investigate the potential effects of HSP preinduction by cold or hot water immersion on trypsin-induced acute pancreatitis in rats. Trypsin was injected into the interlobular tissue of the duodenal part of the pancreas at the peak level of HSP synthesis, as determined by Western blot analysis. The rats were sacrificed by exsanguination through the abdominal aorta 6 h after the trypsin injection. The serum amylase activity, the tumor necrosis factor-alpha, interleukin-1, and interleukin-6 levels, the pancreatic weight/body weight ratio, and the pancreatic contents of DNA, protein, amylase, lipase, and trypsinogen were measured. A biopsy for histology was taken. Hot water immersion significantly elevated the HSP72 expression, while cold water immersion significantly increased the HSP60 expression. Cold water immersion pretreatment ameliorated the pancreatic edema in trypsin-induced pancreatitis, however this was not due to the HSP60. Hot water immersion pretreatment did not have any effect on the measured parameters in trypsin-induced pancreatitis. The findings suggest that the induction of HSP60 or HSP72 are not enough to protect rats against the early phase of this localized necrohemorrhagic pancreatitis model.

Water immersion pretreatment decreases pro-inflammatory cytokine production in cholecystokinin-octapeptide-induced acute pancreatitis in rats: possible role of HSP72.

Heat shock proteins (HSPs) are cytoprotective proteins that are expressed constitutively and/or at elevated levels upon the exposure of cells to stress. The aim of this study was to investigate the potential effects of HSP preinduction by cold- (CWI) or hot-water immersion (HWI) on pro-inflammatory cytokine production (IL-1, IL-6, TNF-alpha) in cholecystokinin-octapeptide(CCK)-induced acute pancreatitis. Rats were injected with 3 x 75 microg/kg CCK subcutaneously at intervals of 2 h at the peak level of HSP synthesis, as determined by Western blot analysis. The animals were killed by exsanguination through the abdominal aorta 2 h after the last CCK injection. The serum IL-1, IL-6, TNF-alpha, and amylase levels, the pancreatic weight/body weight ratio, and the pancreatic contents of DNA, protein, amylase, lipase and trypsinogen were measured; biopsy for histology was taken. HWI significantly elevated the HSP72 expression, while CWI significantly increased the HSP60 expression. HWI pretreatment decreased all of the measured serum cytokine levels in this acute pancreatitis model. CWI and HWI pretreatment ameliorated most of the examined laboratory and morphological parameters of CCK-induced pancreatitis. The findings suggest the possible roles of HSP60 and HSP72 in the protection against CCK-induced pancreatitis. HSP72 might also participate in the reduction of pro-inflammatory cytokine synthesis.

Fluoride concentrations of unstimulated whole and labial gland saliva in young adults after fluoride intake with milk.

Following a fluoride depletion period 6 subjects repeatedly rinsed with 30-ml volumes of milk with or without added fluoride (5 ppm). Rinsing time was timed according to the measurements on how long it took to drink 200 or 500 ml milk. Rinsing with fluoridated milk for a total interval of 20 and 60 s, respectively, did not influence significantly the fluoride concentration of unstimulated centrifuged whole saliva 45 min later. Neither the urinary fluoride concentration nor the fluoride excretion were significantly affected by rinsing with fluoridated milk during the first hour. However, intake of 1 or 2.5 mg of fluoride with 200 and 500 ml milk, respectively, resulted in significant elevations in whole saliva fluoride levels 45 min later. In addition, the fluoride excretions into urine produced during 60 min after the fluoride intakes were significantly elevated and those reflected the ingested dose of fluoride. The intake of either 1 or 2.5mg fluoride with milk did not significantly influence the fluoride level of unstimulated labial gland saliva collected simultaneously with whole saliva.

[The effect of a single-dose intravenous vinpocetine on brain metabolism in patients with ischemic stroke]. / Egyszeri vinpocetin-infúzió agyi anyagcserére gyakorolt hatásának vizsgálata territoriális típusú ischaemiás stroke-ot szenvedett betegeken.

The effect of a single-dose i.v. infusion of vinpocetine on the cerebral blood flow (CBF) and glucose metabolism of post-stroke patients was studied by measuring the regional and global cerebral metabolic rates of glucose (CMRglu) and the corresponding kinetic constants before and after treatment. Transcranial Doppler (TCD) and single photon emission tomography (SPECT) measurements were also performed. The cerebral glucose metabolism was significantly higher in the contralateral hemisphere than in the affected one before therapy. In the affected hemisphere the regional glucose metabolism was inhomogenous: relatively low values were measured in the stroke region, whereas it was increased in the peristroke region. Although a single-dose vinpocetine treatment did not affect significantly the regional or global metabolic rates of glucose, the glucose transport (both intracellular up-take and release) was strongly affected in the whole brain, in the contralateral hemisphere and in the peri-infarct area of the symptomatic hemisphere. A slightly increased (not significant, N. S.) cerebral blood flow could be observed in the contralateral and a decreased flow (N. S.) in the symptomatic hemisphere.

The Ketel gene encodes a Drosophila homologue of importin-beta.

The Drosophila melanogaster Ketel gene was identified via the Ketel(D) dominant female sterile mutations and their ketel(r) revertant alleles that are recessive zygotic lethals. The maternally acting Ketel(D) mutations inhibit cleavage nuclei formation. We cloned the Ketel gene on the basis of a common breakpoint in 38E1. 2-3 in four ketel(r) alleles. The Ketel(+) transgenes rescue ketel(r)-associated zygotic lethality and slightly reduce Ketel(D)-associated dominant female sterility. Ketel is a single copy gene. It is transcribed to a single 3.6-kb mRNA, predicted to encode the 97-kD Ketel protein. The 884-amino-acid sequence of Ketel is 60% identical and 78% similar to that of human importin-beta, the nuclear import receptor for proteins with a classical NLS. Indeed, Ketel supports import of appropriately designed substrates into nuclei of digitonin-permeabilized HeLa cells. As shown by a polyclonal anti-Ketel antibody, nurse cells synthesize and transfer Ketel protein into the oocyte cytoplasm from stage 11 of oogenesis. In cleavage embryos the Ketel protein is cytoplasmic. The Ketel gene appears to be ubiquitously expressed in embryonic cells. Western blot analysis revealed that the Ketel gene is not expressed in several larval cell types of late third instar larvae.

The Ketel(D) dominant-negative mutations identify maternal function of the Drosophila importin-beta gene required for cleavage nuclei formation.

The Ketel(D) dominant female-sterile mutations and their ketel(r) revertant alleles identify the Ketel gene, which encodes the importin-beta (karyopherin-beta) homologue of Drosophila melanogaster. Embryogenesis does not commence in the Ketel(D) eggs deposited by the Ketel(D)/+ females due to failure of cleavage nuclei formation. When injected into wild-type cleavage embryos, cytoplasm of the Ketel(D) eggs does not inhibit nuclear protein import but prevents cleavage nuclei formation following mitosis. The Ketel(+) transgenes slightly reduce effects of the Ketel(D) mutations. The paternally derived Ketel(D) alleles act as recessive zygotic lethal mutations: the Ketel(D)/- hemizygotes, like the ketel(r)/ketel(r) and the ketel(r)/- zygotes, perish during second larval instar. The Ketel maternal dowry supports their short life. The Ketel(D)-related defects originate most likely following association of the Ketel(D)-encoded mutant molecules with a maternally provided partner. As in the Ketel(D) eggs, embryogenesis does not commence in eggs of germline chimeras with ketel(r)/- germline cells and normal soma, underlining the dominant-negative nature of the Ketel(D) mutations. The ketel(r) homozygous clones are fully viable in the follicle epithelium in wings and tergites. The Ketel gene is not expressed in most larval tissues, as revealed by the expression pattern of a Ketel promoter-lacZ reporter gene.

[Diffuse alveolar hemorrhage in systemic lupus erythematosus]. / Diffúz alveolaris haemorrhagia szisztémás lupus erythematosusban.

Of the 120 systemic lupus erythematosus (SLE) patients treated by the authors, two have developed diffuse alveolar haemorrhage. The authors' objective is to present this rare, but severe manifestation. Patients 1 and 2 were 66- and 22-year old women, respectively. Both had SLE with multi-organ involvements including diffuse proliferative lupus nephritis. Before the diagnosis of the disease, both patients had experienced pneumonitis that resolved on corticosteroid treatment. Soon after the diagnosis, respiratory failure, haemoptoea and acute anaemia developed, accompanied by a rapid deterioration in the general condition. Chest radiographs revealed bilateral, diffuse, alveolar infiltrates. The pulmonary haemorrhage temporarily ceased in response to corticosteroid treatment, but both patients later died in consequence of active SLE and mixed bacterial and fungal sepsis. Post mortem examination demonstrated fibrosing alveolitis and alveolar bleeding in Patient 1, and an immune complex deposition-induced alveolocapillary inflammation with alveolar haemorrhage in Patient 2. Diffuse alveolar haemorrhage is a life-threatening manifestation of SLE. Its onset may be preceded by episodes of pneumonitis resolving on corticosteroid treatment. An active diagnostic workup, intensive observation and aggressive immunosuppressive treatment are the cornerstones of the management. The early detection and the active treatment of secondary infections are obligatory. The authors consider the most difficult challenge to be the optimum coordination of the above treatment modalities.

Study of saliva secretion and the salivary fluoride concentration of the human minor labial glands by a new method.

Unstimulated and stimulated flow rate from minor lower labial glands and the fluoride concentration of resting whole and labial saliva were measured over 15 min using a novel method avoiding eversion of the lips. Resting salivary flow rate was measured as 1.09+/-0.44 microl/min/cm2 and stimulated flow rate as 3.13+/-1.05 microl/min/cm2. Secretion rates were significantly (p<0.001) increased during periods of continuous speaking. The increase in secretion elicited by labial movements and speaking may result from mechanical stimulation and/or activity of myoepithelial cells. Fluoride concentrations in resting whole saliva and in unstimulated minor labial gland saliva were 0.066+/-0.048 and 0.181+/-0.073 parts/10(6), respectively. The secretory capacity of the minor labial glands and the high F concentration in their secretions suggests a significant contribution to the F content of whole saliva. Our non-invasive method permits collection from the minor labial glands of a volume large enough for chemical analysis. It should prove useful for studying the effects of different secretory stimuli.

Membrane stretch and salivary glands - facts and theories.

Cell shape in salivary glands is affected by mechanical forces. In the acini and ducts cell shape is modified by the contractions of the myoepithelial cells in both the secretory and ductal portions of the glands. At the organ level shape changes are due to muscle contraction during mastication, food intake and speech. All these factors may cause some degree of stretching of salivary cell membranes. Recent studies suggest that physical forces influence signal transduction, gene expression, secretory function, cell differentiation and proliferation. Here we overview membrane stretch-activated cellular events. Evidence from a variety of tissues suggests that mechanical forces may alter the properties of acinar cells leading to cytoskeletal reorganisation, changes in ion fluxes, modulation of secretory activity and subsequent release of transmitters such as ATP. Transmitters released from acinar cells may modulate the secretory activity of salivary tissue, and interact with classical regulatory pathways.

Preparation and primary evaluation of [11C]CSC as a possible tracer for mapping adenosine A2A receptors by PET.

A 11C labeled selective adenosine A2A antagonist, (E)-8-(3-chlorostyryl)-1,3-dimethyl-7-[11C]methylxanthine [11C]CSC) was prepared by the reaction of (E)-8-(3-chlorostyryl)-1,3-dimethylxanthine and [11C]methyl iodide. The decay-corrected radiochemical yield was 32.3% with a radiochemical purity of 99%, a specific activity of 1.85-5.55 GBq/mumol and a preparation time of 1 h. A primary evaluation of [11C]CSC as a potential tracer for mapping adenosine A2A receptors by positron emission tomography (PET) is also presented. Biodistribution and autoradiographic studies were carried out on Swiss mice and domestic rabbits. In mice the lung showed the highest uptake at 10 min after i.v. injection, followed by the liver, kidney, heart and brain. Inside the brain a high level of radioactivity accumulated in the striatum, in accordance with previous findings on the specific spatial distribution of A2A adenosine receptors and also in the medulla oblongata. Dynamic PET studies on rabbits showed a fast brain uptake of CSC, reaching a maximum in less then 2 min. On the basis of competition experiments with the unlabeled ligand [11C]CSC proves to bind specifically to the appropriate receptor.

Cerebral effects of a single dose of intravenous vinpocetine in chronic stroke patients: a PET study.

The effects of vinpocetine (Cavinton) on the cerebral glucose metabolism of chronic stroke patients are studied with positron emission tomography. The regional and global cerebral metabolic rates of glucose (CMRglu) and the kinetic constants related to them are quantified before and after single-dose intravenous vinpocetine treatment. These measurements are completed with transcranial Doppler sonography and single photon emission computed tomography to explore the possible mechanisms underlying the resulting changes in glucose uptake and metabolism in the brain. The authors' findings indicate that a single-dose vinpocetine treatment, although it does not affect significantly the regional or global metabolic rates of glucose, improves significantly the transport of glucose (both uptake and release) through the blood-brain barrier in the whole brain, the entire contralateral hemisphere, and in the brain tissue around the infarct area of the symptomatic hemisphere. These changes are in accord with increased blood flow in the entire contralateral hemisphere as well as decreased blood flow velocity and increased peripheral vessel resistance in the entire symptomatic hemisphere.

An extended alpha-helix and specific amino acid residues opposite the DNA-binding surface of the cAMP response element binding protein basic domain are important for human T cell lymphotropic retrovirus type I Tax binding.

The human T cell lymphotropic retrovirus type I (HTLV-I) trans-activator, Tax, interacts specifically with the basic-domain/leucine-zipper (bZip) protein, cAMP response element binding protein (CREB), bound to the viral Tax-responsive element consisting of three imperfect 21-base pair repeats, each with a cAMP response element core flanked by G/C-rich sequences. Here, the minimal CREB-bZip necessary for Tax binding is shown to be composed of amino acid residues 280-341. The Tax-CREB interaction involves an uninterrupted and extended alpha-helix in CREB that spans most of its basic domain to include amino acid residues localized to the NH2 terminus of the DNA binding region. Mutational analyses indicate that three residues, Arg284, Met291, and Glu299 unique to this region of the CREB/activating transcription factor-1 subfamily of bZip proteins, constitute the contact surface for Tax. Amino acid substitutions in these positions had little impact on CREB-bZip binding to DNA but abrogated its binding to Tax. Each of the contact residues for Tax are spaced approximately two helical turns apart on the side of the bZip helix directly opposite to that of the invariant DNA-binding residues. Molecular modeling reveals the Tax-contact residues to be near the minor groove of the G/C-rich DNA in the 21-base pair repeat. They most likely position Tax for minor groove contact with the G/C-rich sequences.

The Tomaj mutant alleles of alpha Tubulin67C reveal a requirement for the encoded maternal specific tubulin isoform in the sperm aster, the cleavage spindle apparatus and neurogenesis during embryonic development in Drosophila.

The three dominant TomajD and their eleven revertant (TomajR) alleles have been localized to the alpha Tubulin67C gene of Drosophila melanogaster. Although the meiotic divisions are normally completed in eggs laid by TomajD/+, TomajD/-, TomajR/- females, embryogenesis arrests prior to the gonomeric division. The arrest is caused by: (1) the failure of prominent sperm aster formation; and (2) a consequent lack of female pronuclear migration towards the male pronucleus. Concomitant with the sperm aster defect, the four female meiotic products fuse (tetra-fusion), similar to what is seen in eggs of wild-type virgin females. In eggs of females heterozygous for weaker TomajR alleles, embryogenesis comes to a cessation before or shortly after cortical migration of cleavage nuclei. The apparent source of embryonic defect is the cleavage spindle apparatus. One of the three TomajD alleles is cold-sensitive and its cold-sensitive period coincides with the completion of female meiosis and pronuclear migration. Disorganized central and peripheral nervous systems are also characteristic of embryos derived from the temperature-sensitive TomajD/+ females. The Tomaj mutant phenotypes indicate an involvement of the normal alpha Tubulin67C gene product in: (1) the formation of the sperm aster; (2) cleavage spindle apparatus formation/function; and (3) the differentiation of the embryonic nervous system. The TomajD alleles encode a normal-sized alpha Tubulin67C isotype. Sequence analyses of the TomajD alleles revealed the replacement in different positions of a single negatively charged or neutral amino acid with a positively charged one. These residues presumably identify important functional sites.