The C-terminal domain of MinC inhibits assembly of the Z ring in Escherichia coli.

In Escherichia coli, the Min system, consisting of three proteins, MinC, MinD, and MinE, negatively regulates FtsZ assembly at the cell poles, helping to ensure that the Z ring will assemble only at midcell. Of the three Min proteins, MinC is sufficient to inhibit Z-ring assembly. By binding to MinD, which is mostly localized at the membrane near the cell poles, MinC is sequestered away from the cell midpoint, increasing the probability of Z-ring assembly there. Previously, it has been shown that the two halves of MinC have two distinct functions. The N-terminal half is sufficient for inhibition of FtsZ assembly, whereas the C-terminal half of the protein is required for binding to MinD as well as to a component of the division septum. In this study, we discovered that overproduction of the C-terminal half of MinC (MinC(122-231)) could also inhibit cell division and that this inhibition was at the level of Z-ring disassembly and dependent on MinD. We also found that fusing green fluorescent protein to either the N-terminal end of MinC(122-231), the C terminus of full-length MinC, or the C terminus of MinC(122-231) perturbed MinC function, which may explain why cell division inhibition by MinC(122-231) was not detected previously. These results suggest that the C-terminal half of MinC has an additional function in the regulation of Z-ring assembly.

Fibrillins: Sequence, phylogeny and carboxy terminal domain proteolytic processing

Fibrillin-1 and -2 are large secreted glycoproteins that are known to be components of extracellular matrix microfibrils located in the vasculature, basement membrane and various connective tissues. These microfibrils are often associated with a superstructure known as the elastic fiber. During the development of elastic tissues, fibrillin microfibrils precede the appearance of elastin and may provide a scaffolding for the deposition and crosslinking of elastin. Using RT/PCR, we cloned and sequenced 3.85Kbp of the FBN2 gene. Five differences were found between our contig sequence and that published by Zhang et al. (1995). Like many extracellular matrix proteins, the fibrillins are modular proteins. We compared analogous domains of the two fibrillins and also members of the latent TGF-$\beta$ binding protein (LTBP) family to determine their phylogenetic relationship. We found that the two families are homologous. LTBP-2 is the most similar to the fibrillin family while FBN-1 is the most similar to the LTBP family. The fibrillin-1 carboxy terminal domain is proteolytically processed. Two eukaryotic protein expression systems, baculoviral and CHO-K1, were developed to examine the proteolytic processing of the carboxy terminal domain of the fibrillin-1 protein. Both expression systems successfully processed the domain and both processed a mutant less efficiently. In the CHO-K1 cells, processing occurred intracellularly. ^

Maternal health care utilization in rural Jordanian villages: Patterns and predictors

Background. Different individual (demographic) characteristic and health system related characteristics have been identified in the literature to contribute to different rates of maternal health care utilization in developing countries. This study is going to evaluate the individual and quality of health predictors of maternal health care utilization in rural Jordanian villages. ^ Methods. Data from a 2004 survey was used. Individual (predisposing and enabling) variables, quality of health care variables, and maternal care utilization variables were selected for 477 women who had a live birth during the last 5 years. The conceptual framework used in this study will be the Aday-Andersen model for health services utilization. ^ Results. 82.4% of women received at least one antenatal care visit. Individually, village of residence (p=0.036), parity (p=0.048), education (p=0.006), and health insurance (p=0.029) were found to be significant; in addition to respectful treatment (p=0.045) and clean facilities (p=0.001) were the only quality of health care factors found to be significant in predicting antenatal care use. Using logistic regression, living in southern villages (OR=4.7, p=0.01) and availability of transportation (sometimes OR=3.2, p=0.01 and never OR=2.4, p<0.05) were the only two factors to influence maternal care use. ^ Conclusions. Living in the South and transportation are major barriers to maternal care utilization in rural Jordan. Other important cultural factors of interest in some villages should be addressed in future research. Perceptions of women regarding quality of health services should be seriously taken into account. ^

THE POTENTIAL EFFECTS OF A COMMUNITY DEVELOPMENT PROGRAM ON DEMOGRAPHIC VARIABLES IN HIMALAYAN INDIAN VILLAGES

A community development program operating in the mountains of North India was studied to assess its potential effects on mortality, fertility and migration patterns in the community which it served. The development program operated in Jaunpur Block, Tehri-Garhwal District, Uttar Pradesh State. Two comparable villages in the district were studied. The development program had been working in one for two years, and the other was completely untouched by the program.^ Since not enough time had elapsed since the beginning of the development program's work for any effects on demographic patterns to be visable in Jaunpur Block, this study looked to attitudes of village residents as indicators of future demographic trends. Existing demographic patterns and their interrelationship with socio-religious customs were examined in the test village. A questionnaire was then administered to ascertain attitudinal differences between the residents of the test village and the control village.^ The primary work of the community development program was to train women as village health workers. The results of the attitudinal comparison of the residents of the two villages showed a marked difference in attitudes relating to the position of women in society. The data showed a higher esteem for women in the test village than in the control village, and it is argued that this difference may be attributable to the work of the development program.^ Predicting future demographic trends in Jaunpur Block on the basis of the observed difference in villagers' attitudes toward the status of women is speculatory. Jaunpur Block appears to be in the demographic stage of pre-transition, maintaining relatively high rates of both mortality and fertility. Based on demographic transition theory the next significant change in demographic patterns in Jaunpur is predicted to be a decline in mortality, and an increase in the status of women is unrelated to this prediction.^ The community development program which was studied terminated unexpectedly during the time of this study. A case study of the program's final months is presented, and speculation on the future course of demographic trends in Jaunpur Block is related to the possible alternatives for future development in the area. ^

The role of the conserved N -terminal domain of STAT3 in STAT3 dephosphorylation and nuclear export

Rapid redistribution of STAT subcellular localization is an essential feature of cytokine signaling. To elucidate the molecular basis of STAT3 function, which plays a critical role in controlling innate immune responses in vivo, we initiated studies to determine the mechanisms controlling STAT3 nuclear trafficking. We found that STAT3 is transported to the nucleus in the absence of cytokine treatment, as judged by indirect immunofluorescence studies in the presence of leptomycin B, an inhibitor of CRM1-dependent nuclear export, suggesting that the non-phosphorylated STAT3 protein contains a functional nuclear import signal. An isoform lacking the STAT3 N-terminal domain (Δ133STAT3) retains the ability to undergo constitutive nuclear localization, indicating that this region is not essential for cytokine-independent nuclear import. Δ133STAT3 is also transported to the nucleus following stimulation with interleukin-6 (IL-6). Interestingly, IL-6-dependent tyrosine phosphorylation of Δ133STAT3 appears to be prolonged and the nuclear export of the protein delayed in cells expressing endogenous STAT3, consistent with defective Δ133STAT3 dephosphorylation. Endogenous STAT3 does not promote the nuclear export of Δ133STAT3, although dimerization between endogenous Stat3 and Δ133STAT3 is detected readily. Thus, the STAT3 N-terminal domain is not required for dimerization with full-length STAT3, yet appears to play a role in proper export of Stat3 from the nucleus following cytokine stimulation. STAT3-deficient cells reconstituted with Δ133STAT3 show enhanced and prolonged Stat1 signaling in response to IL-6, suggesting that induction of the STAT3-dependent negative regulator SOCS3 is impaired. In fact, Δ133STAT3 fails to induce SOCS3 mRNA efficiently. These studies collectively indicate that the STAT3 N-terminal region may be important for IL-6-dependent target gene activation and nuclear dephosphorylation, while dispensable for nuclear import. STAT3 is an oncogene. STAT3 is constitutively activated in primary tumors of many types. Thus far, research in the design of STAT3 protein inhibitors has focused on the SH2 and DNA-binding domains of STAT3. Interference with these domains eliminates all signaling through STAT3. If the N-terminal domain is involved in tetramerization on a subset of target genes, inhibition of this region may lead to a more selective inhibition of some STAT3 functions while leaving others intact. ^