Analysis of the C-terminal region of Arabidopsis thaliana APETALA1 as a transcription activation domain

APETALA1 (AP1) of Arabidopsis thaliana is a transcription factor controlling flower development. AP2 is a member of the MADS (MCM1, AGAMOUS, DEFICIENS, SRF) superfamily, which plays important roles in differentiation in plants and animals. MADS domains, which function most importantly in DNA binding, are found in all major eukaryotic kingdoms. In plants, MADS domain-containing proteins also possess a region of moderate sequence similarity named the K domain, which is involved in protein-protein interaction. Little is known about the function of a third, highly variable, domain designated the C domain, as it resides at the C terminus of the MADS proteins of plants. Here we report that the C-terminal domain of Arabidopsis thaliana AP1 and its homologues perform a transcriptional activation function. The C-terminal region of AP1 is composed of at least two separable transcriptional activation domains that function synergistically.

Analysis of the C-terminal region of Arabidopsis thaliana APETALA1 as a transcription activation domain

APETALA1 (AP1) of Arabidopsis thaliana is a transcription factor controlling flower development. AP2 is a member of the MADS (MCM1, AGAMOUS, DEFICIENS, SRF) superfamily, which plays important roles in differentiation in plants and animals. MADS domains, which function most importantly in DNA binding, are found in all major eukaryotic kingdoms. In plants, MADS domain-containing proteins also possess a region of moderate sequence similarity named the K domain, which is involved in protein-protein interaction. Little is known about the function of a third, highly variable, domain designated the C domain, as it resides at the C terminus of the MADS proteins of plants. Here we report that the C-terminal domain of Arabidopsis thaliana AP1 and its homologues perform a transcriptional activation function. The C-terminal region of AP1 is composed of at least two separable transcriptional activation domains that function synergistically.

Expressed sequence tags of radish flower buds and characterization of a CONSTANS LIKE 1 gene

Expressed sequence tag (EST) analysis was conducted for young flower buds of radish plants. Among a total of 66 ESTs examined, 40 showed a significant similarity to previously identified genes. Twenty-eight ESTs were similar to proteins identified in other plants, 11 were similar to eukaryotic proteins other than plants, and one was similar to a prokaryotic protein. Four clones were selected for further studies. EST clone 81, which showed a homology to germin-like proteins was expressed more abundantly in leaves and roots as compared to flower buds. Clone 105 was highly homologous to the translation inhibitor protein and was expressed in all three organs, but the expression level was higher in flower buds and roots. Another EST clone, 133, which shared a significant similarity with the Ran-binding protein, hybridized to two different size transcripts that were detectable only in flower buds. Clone 39 was a homolog of CONSTANS, which is a gene involved in controlling the flowering time in Arabidopsis. The cDNA clone of EST clone 39 containing the entire open reading frame was obtained and designated as RsCOL1 (Raphanus sativus CONSTANS LIKE 1). It was 1049 bp long and contained an open reading frame of 307 amino acid residues (calculated molecular mass = 33.1 kDa). The RsCOL1 protein contained two putative zinc finger motifs in the amino terminal region which were 59% identical to the corresponding region of the Arabidopsis CO protein. The radish protein also contained a predicted nuclear localization domain in the carboxyl terminal region which was 87% identical to the corresponding region of CO. DNA blot analysis revealed that the radish genome contained several genes similar to RsCOL1. RNA blot analysis showed that RsCOL1 was strongly expressed in flower buds at the early bolting stage, and the expression level declined as the flower bud matured. The transcript was also detectable in leaves and roots. In mature flowers, the RsCOL1 transcript was present primarily in carpels.

Controlling the judge variable in grading essay-type items: an application of Rasch analyses to the recruitment exam for Korean public school teachers

The purpose of this paper is to show how the Rasch measurement model can be used to control the effects of judge variable on the grading of essay-type items in the recruitment test for Korean teachers. Special attention is given to two aspects of judges' involvement in the grading. One is to identify a way to minimize the variation of grading due to judge severity. The other concern is to figure out a way to reduce the number of judges without threatening objectivity of ability estimates. Results from the FACETS analyses tell us not only how much grading standards vary among judges and how to adjust them but also it produces comparably reliable ability estimates with fewer judges.

Cloning and sequence analysis of the cDNA encoding the elongation factor-1 beta of Dictyostelium discoideum

A cDNA encoding elongation factor-1 beta (DdEF-1 beta) for protein synthesis was isolated from Dictyostlium discoideum cells by the differential display (DD) method. The DdEF-1 beta cDNA sequence with a length of 733 bp encodes a protein (M(r) 24.1 kDa) consisting of 214 amino acids. Comparison of the predicted amino acid sequence revealed relatively high homology to that of DdEF-1 beta from silkworm (59%), human (57%) and Xenopus (55%). Northern analysis showed that the DdEF-1 beta mRNA is maximally expressed during the vegetative growth phase, followed by marked decrease in response to cell differentiation induced by starvation.

Uvula-nodulus and gravity direction (a study on vertical optokinetic-oculomotor functions)

Some characteristics of vertical optokinetic nystagmus and after-nystagmus, in particular, its up/down gain asymmetry, are known to be influenced by gravity direction, which is basically perceived by otolith organs. However, how such an information of gravity direction is processed within the central nervous system is not well understood, even though the role of cerebellar uvula and nodulus in vertical eye movements has been identified for some time. Accordingly, in this study, vertical optokinetic nystagmus and after-nystagmus were studied in squirrel monkeys both in the upright and side-lateral positions (different gravity direction to the head), before and after uvulonodulectomy. When the optokinetic stimulus was given, the slow phase eye velocity of optokinetic nystagmus was significantly higher in the side-lateral position than that obtained in the upright position. This difference disappeared after uvulonodulectomy. When the initial slow phase eye velocity of optokinetic after-nystagmus was compared, the one obtained in the side-lateral position was significantly higher than that acquired in the upright position. This difference also disappeared after the uvulonodular ablation. Thus, in this study of vertical optokinetic nystagmus and after-nystagmus, the role of uvula and nodulus in relaying the information of gravity direction was confirmed.

Lymphoid development in mice congenitally lacking T cell receptor alpha beta-expressing cells

Vertebrate T cells express either an alpha beta or gamma delta T cell receptor (TCR). The developmental relatedness of the two cell types is unresolved. alpha beta + T cells respond to specific pathogens by collaborating with immunoglobulin-producing B cells in distinct lymphoid organs such as the spleen and Peyer's patches. The precise influence of alpha beta + T cells on B cell development is poorly understood. To investigate the developmental effects of alpha beta + T cells on B cells and gamma delta + T cells, mice homozygous for a disrupted TCR alpha gene were generated. The homozygotes showed elimination of alpha beta + T cells and the loss of thymic medullae. Despite this, gamma delta + T cells developed in normal numbers, and there was an increase in splenic B cells.

Compensation of vertical vestibulo-ocular functions in squirrel monkeys after unilateral labyrinthectomy

Modifications in the vertical vestibulo-ocular reflex (VVOR) were studied in four squirrel monkeys (Saimiri sciureus) over time after unilateral labyrinthectomy. In the dark, with head upright, animals were exposed to sinusoidal rotation in the pitch plane. The magnetic field-pericorneal search coli technique was used to detect eye movement. The upward and downward slow-phase eye velocity (SPEV) of the VVOR and the maximum SPEV of the vertical component of spontaneous nystagmus (SPN) were studied. The mean preoperative gain of VVOR was symmetric. After unilateral labyrinthectomy, the maximum reduction of VVOR gain showed an asymmetry. The recovery of VVOR gain to the preoperative level took about 2 weeks, and the vertical component of SPN was present for about 3 weeks.

Autonomic indexes during the vestibular-visual conflict exposure: a squirrel monkey study

To assess the dynamic changes of the autonomic neural responses evoked by vestibular-visual conflict (VVC) in the squirrel monkey, we analyzed the changes of salivary amount and sodium concentration, and the coefficient of variance (CV) of R-R intervals (RRI) along the time course of VVC exposure given in pitch plane. The sodium concentration and the amount of saliva showed clear increases at the first and second 15 min stimulation periods. The CV of RRI was found to increase over the entire periods of stimulation, and there was a significant difference between the rest value and those in stimulated periods. The correlation between the CV of RRI, and amount of salivation was highly positive. These results indicate the existence of a common pattern of autonomic neural response during VVC, and suggest usefulness of these indexes for objectively monitoring the severity of motion sickness.

Second-phase optokinetic after-nystagmus and vestibular compensation

To evaluate the direction-specific effect of optokinetic storage function on balance compensation after unilateral labyrinthectomy, squirrel monkeys (n = 12) were exposed to a prolonged (30 min) daily optokinetic stimulus (horizontal, constant speed-90 degrees/sec) for 14 days; either in the ipsilateral direction to the slow phase of spontaneous nystagmus, or in the contralateral direction, or without any optokinetic stimulus. The effect of optokinetic stimulus in ipsilateral direction (slow phase of OKAN-II in the opposite direction) was significantly more (p less than 0.001) in the vestibulo-oculomotor balance (static) regainment than the other two groups, but this group showed the severest gait deviation in the vestibulospinal balance function (p less than 0.05).

Insulin patterns in equivocal glucose tolerance tests (chemical diabetes)

Hyperinsulinemic patterns are a well recognized feature of equivocal glucose tolerances of the chemical diabetes type, i.e. those that are neither definitely nondiabetic nor clearly diabetic. A more complete characterization of such insulin responses is obtained when the data are expressed in terms of increments in insulin from the zero time point.

Thus, two patterns of insulin increments after oral glucose become evident when the equivocal zone of glucose tolerance is divided into lower and upper segments. Tests in the lower segment show normal increments at the halfhour point of the test; at one hour these tests show excessive increments which persist throughout the five hours of observation. On the other hand, tests in the upper zone show delays in the serum insulin rise at the half-hour point, followed by normal increments at one hour and excessive increments thereafter. The pattern is the same whether or not obesity is present.

It is suggested that tests in the equivocal zone of Glucose Tolerance Sum values be taken to be indicative of chemical diabetes. Tests with the Sum in the lower half of the equivocal zone could then represent chemical diabetes with mild intolerance stemming from insulin ineffectiveness, since insulin increments in this group are at or above the mean values recorded in nondiabetic controls. On the other hand, chemical diabetes with moderate glucose intolerance and Glucose Tolerance Sums in the upper half of the equivocal zone would be understood to result from a combination of an initial delay in the serum insulin rise followed by normal and then excessive increments in serum insulin with the latter two indicative of insulin ineffectiveness. However, insulin ineffectiveness may also be present at the time of the insulin delay.

High glucose:insulin ratios in tests indicative of chemical diabetes are almost always attributable to higher glucose increments with insulin increments normal or excessive compared to normal glucose tolerances. Deficient insulin increments contribute to the high ratios only at the half-hour point in tests with Glucose Tolerance Sums in the upper zone of equivocal glucose tolerances.