Spermatogenic
cells elaborate a highly specialized differentiation program that is mediated in part by germ cell-enriched transcription
factors. This includes a novel member of the sterol response ...element-binding factor family, SREBF2_v1/SREBP2gc. Somatic SREBFs
are predominantly synthesized as precursor proteins and are critical regulators of cholesterol and fatty acid synthesis. In
contrast, SREBF2_v1 bypasses the precursor pathway and has been directly implicated in spermatogenic cell-specific gene expression.
During spermatogenesis, SREBF2 precursor transcripts predominate in premeiotic stages, while SREBF2_v1 is highly upregulated
specifically in pachytene spermatocytes and round spermatids. In the present study, we demonstrate that
Srebf2_v1
mRNAs are present in the testis of several mammalian species, including humans. The basis for the stage-dependent transition
in SREBF2 isoforms was also investigated. A 3' rapid amplification of cDNA ends (RACE)-PCR analysis of the rat and human revealed
that
Srebf2_v1
transcripts are generated by alternative pre-mRNA cleavage/polyadenylation. This involves the use of an intronic, A(A/U)UAAA-independent
poly(A) signal within intron 7 of the
Srebf2
gene. Developmentally regulated competition between germ cell factors that control RNA splicing and pre-mRNA cleavage/polyadenylation
may underlie this process. These results define an important role for alternative polyadenylation in male germ cell gene expression
and development by controlling a stage-dependent switch in transcription factor structure and function during spermatogenesis.
The
Srebf2
gene thus provides a useful model to explore the role of alternative polyadenylation in regulating stage-dependent functions
of important protein regulators in spermatogenic cells.
Abstract
Spermatogenic cells regulate SREBF2 transcription factor function by a stage-dependent shift from pre-mRNA splicing to alternative
polyadenylation, converting it into a sterol-insensitive form that activates germ cell-specific gene expression.
Neuronal voltage-gated sodium channel Na
1.2 C-terminal domain (CTD) binds calmodulin (CaM) constitutively at its IQ motif. A solution structure (6BUT) and other NMR evidence showed that the CaM N ...domain (CaM
) is structurally independent of the C-domain (CaM
) whether CaM is bound to the Na
1.2
(1,901-1,927) or Na
1.2
(1,777-1,937) with or without calcium. However, in the CaM + Na
1.2
complex, the Ca
affinity of CaM
was more favorable than in free CaM, while Ca
affinity for CaM
was weaker than in the CaM + Na
1.2
complex. The CTD EF-like (EFL) domain allosterically widened the energetic gap between CaM domains. Cardiomyopathy-associated CaM mutants (N53I(N54I), D95V(D96V), A102V(A103V), E104A(E105A), D129G(D130G), and F141L(F142L)) all bound the Na
1.2 IQ motif favorably under resting (apo) conditions and bound calcium normally at CaM
sites. However, only N53I and A102V bound calcium at CaM
sites at Ca
< 100 μM. Thus, they are expected to respond like wild-type CaM to Ca
spikes in excitable cells.
Leukemia inhibitory factor (LIF) is a pleiotropic molecule of the interleukin 6 family of cytokines. We aimed to examine the safety, pharmacokinetics, and biological effects of recombinant human LIF ...(rhLIF, emfilermin) in patients with advanced cancer.
In stage 1 of the study, 34 patients received rhLIF or placebo (3:1 ratio) at doses of 0.25-16.0 micro g/kg/day or 4.0 micro g/kg three times daily for 7 days. In stage 2, 40 patients received rhLIF or placebo, either once daily for 14 days commencing the day after chemotherapy (0.25-8.0 micro g/kg/day) or for 7 days commencing the day before chemotherapy (4.0 micro g/kg three times daily). The chemotherapy was cisplatin 75 mg/m(2) and paclitaxel 135 mg/m(2).
In stage 1, platelet counts increased in most patients, including those who received placebo. Blood progenitor cells increased in response to rhLIF. In stage 2, platelet recovery to baseline levels was earlier for patients receiving higher doses of rhLIF (>/=4.0 micro g/kg/day; P = 0.02). The neutrophil nadir after chemotherapy was less severe in patients receiving >/=4.0 micro g/kg/day of rhLIF. In stages 1 and 2, increases in C reactive protein were seen at higher doses. Several patients developed evidence of autonomic dysfunction, in particular impotence and episodic hypotension. The dose-limiting toxicities were hypotension and rigors. Pharmacokinetic studies demonstrated a short half-life (1-5 h) independent of dose.
We demonstrated a biological effect of rhLIF on blood progenitor cells, C reactive protein levels, and hemopoietic recovery after chemotherapy.
Herbage from the first regrowth of perennial ryegrass‐based swards was directly ensiled after treatment with a bacterial inoculant/enzyme preparation (SIL‐ALL, Alltech UK) at 3·0 1 t−1, formic acid ...(850 g kg−1) at 2·59 1 t−1 or no additive (Control). The mean dry matter (DM) and water‐soluble carbohydrate concentrations of the grass were 185 and 24·0 g kg−1 (fresh basis) respectively. Lactic acid concentrations after ensiling increased at a lower rate in formic acid‐treated herbage than with the other treatments. All silages were well preserved and formic acid‐treated silage had a lower ultimate concentration of lactic acid and higher concentration of water‐soluble carbohydrate. Effluent output was increased on a proportional basis by ≊0·06 with formic treatment, whereas the inoculant reduced effluent output by 0·05 in comparison with the mean effluent production of the control silage. The in vivo digestibilities of the silages were determined using sheep. The digestibilities of DM, organic matter and energy were significantly higher with inoculant‐treated silage than with formic acid treatment, whereas values for the control silage were intermediate. The three silages were offered ad libitum to forty dairy cows with individual recording of daily intakes for a 10‐week period in a randomized block experiment with four treatments. Sixteen animals were offered the control silage with half of these offered 3 kg concentrates per day (C3) and the other half offered 7 kg concentrates per day (C7). Twelve animals were allocated to each of the additive‐treated silages, with concentrates offered at 5 kg d−1. Treatment effects on animal performance were measured in weeks 7–10. To compare animal performance for the treated silages with the control, an estimate of performance at 5 kg concentrates per day was obtained by regression using values obtained at 3 and 7 kg concentrates. In comparison with estimated silage intake for the control silage with 5 kg d−1 concentrates, inoculant and formic acid treatment of the silages increased dry matter intake by 0·04 (P > 0·05) and 0·13 (P > 0·01) respectively. In comparison with estimated milk production and yield of fat plus protein for the control treatment with 5 kg d−1 concentrates, neither inoculant treatment nor formic acid treatment produced any significant differences.
We present the discovery of the radio afterglow and near-infrared (NIR) counterpart of the Swift short GRB 200522A, located at a small projected offset of \(\approx 1\) kpc from the center of a ...young, star-forming host galaxy at \(z=0.5536\). The radio and X-ray luminosities of the afterglow are consistent with those of on-axis cosmological short GRBs. The NIR counterpart, revealed by our HST observations at a rest-frame time of \(\approx2.3\) days, has a luminosity of \(\approx (1.3-1.7) \times 10^{42}\) erg s\(^{-1}\). This is substantially lower than on-axis short GRB afterglow detections, but is a factor of \(\approx 8\)-\(17\) more luminous than the kilonova of GW170817, and significantly more luminous than any kilonova candidate for which comparable observations exist. The combination of the counterpart's color (\(i-y = -0.08\pm 0.21\); rest-frame) and luminosity cannot be explained by standard radioactive heating alone. We present two scenarios to interpret the broad-band behavior of GRB 200522A: a synchrotron forward shock with a luminous kilonova (potentially boosted by magnetar energy deposition), or forward and reverse shocks from a \(\approx14^{\circ}\), relativistic (\(\Gamma_0 \gtrsim 80\)) jet. Models which include a combination of enhanced radioactive heating rates, low-lanthanide mass fractions, or additional sources of heating from late-time central engine activity may provide viable alternate explanations. If a stable magnetar was indeed produced in GRB 200522A, we predict that late-time radio emission will be detectable starting \(\approx 0.3\)-\(6\) years after the burst for a deposited energy of \(\approx 10^{53}\) erg. Counterparts of similar luminosity to GRB 200522A associated with gravitational wave events will be detectable with current optical searches to \(\approx\!250\) Mpc.
Purpose Hypersensitivity to visceral stimuli in interstitial cystitis/painful bladder syndrome may result from enhanced responsiveness of affective circuits (including the amygdala complex) and ...associated central pain amplification. Potentiation of the eyeblink startle reflex under threat is mediated by output from the amygdala complex and, therefore, represents a noninvasive marker to study group differences in responsiveness in this brain circuit. Materials and Methods Acoustic startle responses were examined in female patients with interstitial cystitis/painful bladder syndrome (13) and healthy controls (16) during context threat (application of muscle stimulation electrodes to the lower abdomen overlying the bladder), and cued conditions for safety (no stimulation possible), anticipation and imminent threat of aversive abdominal stimulation over the bladder. Results Patients showed significantly greater startle responses during nonimminent threat conditions (baseline, safe and anticipation periods) while both groups showed similar robust startle potentiation during the imminent threat condition. Higher rates of anxiety and depression symptoms in the patient group did not account for the group differences in startle reflex magnitude. Conclusions Compared to controls, female patients with interstitial cystitis/painful bladder syndrome showed increased activation of a defensive emotional circuit in the context of a threat of abdominal pain. This pattern is similar to that previously reported in patients with anxiety disorders as well as those with irritable bowel syndrome. Since these circuits have an important role in central pain amplification related to affective and cognitive processes, these results support the hypothesis that the observed abnormality may be involved in the enhanced perception of bladder signals associated with interstitial cystitis/painful bladder syndrome.
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