Surfactant protein (SP)-

PurposeTo determine the individual and combined effects of a simplified form and a review/retest intervention on biobanking consent comprehension.MethodsA national online survey in which participants were randomized within four educational strata to review a simplified or traditional consent form. Participants completed a comprehension quiz after which, for each item answered incorrectly, they reviewed the corresponding consent form section and answered another quiz item on that topic.ResultsConsistent with our first hypothesis, comprehension among those who received the simplified form was not inferior to those who received the traditional form. Contrary to expectations, receipt of the simplified form did not result in significantly better comprehension compared to the traditional form among those in the lowest educational group. The review/retest procedure significantly improved quiz scores in every combination of consent form and education level. Although improved, comprehension remained a challenge in the lowest education group. Higher quiz scores were significantly associated with willingness to participate.ConclusionEnsuring consent comprehension remains a challenge, but simplified forms have virtues independent of their impact on understanding. A review/retest intervention may have a significant effect, but assessing comprehension raises complex questions about setting thresholds for understanding and consequences of not meeting them.

Expression of the surfactant protein-A (SP-A) gene is lung specific and is developmentally and hormonally regulated in fetal lung tissue. Cyclic AMP analogs and glucocorticoids stimulate transcriptional activity of the SP-A gene in fetal rabbit lung tissue in culture; an additive effect is observed when the agents are added in combination. To analyze the genomic regions that regulate SP-A promoter activity, fusion genes comprised of -1766, -991, -378, and -47 basepairs (bp) of DNA flanking the 5'-end of the SP-A gene, the transcription initiation site, and 20 bp of exon I linked to the human GH (hGH) structural gene were subcloned into a replication-defective human adenovirus vector and transfected into differentiated rat type II cells in primary culture. SP-A promoter activity was analyzed by RIA of hGH protein in the culture medium. In type II cells transfected with SP-A-1766:hGH and SP-A-991:hGH fusion genes, hGH production was induced 30- to 40-fold by (Bu)2AMP (Bt2cAMP; 1 mM). When type II cells were transfected with the SP-A-378:hGH fusion gene, basal levels of expression were reduced by more than 50%; however, Bt2cAMP caused an 11-fold increase in hGH production. In type II cells transfected with the SP-A-47:hGH fusion gene, basal levels of hGH production were essentially undetectable, and no stimulatory effect of Bt2cAMP was apparent. Cyclic AMP stimulation of expression of the SP-A-1766:hGH, SP-A-991:hGH, and SP-A-378:hGH fusion genes was limited to type II pneumonocytes in primary culture and was absent in two lung adenocarcinoma cell lines (NCl-H358 and A549), which do not express SP-A, and in cAMP-responsive adrenal Y1 cells. Mutations of a putative cAMP-responsive element (TGACCTCA) at -261 bp revealed its functional importance in mediating cAMP regulation of SP-A gene expression. Unexpectedly, dexamethasone (Dex; 10(-7) M) antagonized the stimulatory effect of Bt2cAMP on expression of SP-A:hGH fusion genes containing from -378 to -1766 bp of 5'-flanking DNA as well as that of a fusion gene construct containing -991 bp of 5'-flanking DNA, the first exon, the first intron, and 20 bp of the second exon (SP-A-991+670:hGH). The inhibitory effect of Dex was dose dependent, with half-maximal inhibition occurring at a Dex concentration of 8 x 10(-10) M. The inhibitory effect of Dex was prevented by the glucocorticoid receptor antagonist RU486.(ABSTRACT TRUNCATED AT 400 WORDS)

Expression of the rabbit pulmonary surfactant protein A (SP-A) gene is lung-specific, occurs primarily in type II cells, and is developmentally regulated. We previously identified two E-box-like enhancers, termed the distal binding element (DBE) and proximal binding element (PBE), in the 5-flanking region of the rabbit SP-A gene. In the present study, the PBE was used to screen a rabbit fetal lung cDNA expression library; a cDNA insert was isolated which is highly similar in sequence to human upstream stimulatory factor 1 (hUSF1). By use of reverse transcription polymerase chain reaction, two isoforms of rabbit USF1 (

Surfactant protein (SP) A gene transcription is developmentally regulated and stimulated by hormones and factors that increase intracellular cAMP. The baboon (b) genome contains two highly similar SP-A genes, bSP-A1 and bSP-A2. With the use of a ribonuclease protection assay with gene-specific probes, the two bSP-Agenes were found to be differentially regulated during baboon fetal lung development in that expression of the bSP-A2 gene appeared to be induced to a high level at a later time in gestation than that of the bSP-A1 gene. Both the bSP-A1 and bSP-A2 genes were found to be highly responsive to the inductive effects of cAMP in baboon fetal lung explants in culture. By DNase I footprinting and electrophoretic mobility shift assays with bacterially expressed thyroid transcription factor-1 (TTF-1) and type II cell nuclear extracts, three TTF-1 binding elements were identified within the 255-bp region flanking the 5′-end of each bSP-A gene; however, these differed in position and spacing for the two bSP-A genes. To functionally define the genomic regions that are required for cAMP regulation of bSP-A gene expression in type II cells, fusion genes composed of various amounts of 5′-flanking DNA from the bSP-A1 and bSP-A2 genes linked to the human growth hormone structural gene as a reporter were transfected into type II cells in primary culture. We found that 255 bp of 5′-flanking DNA, which contain three TTF-1 binding elements, from bSP-A1 and bSP-A2 genes were sufficient to mediate high basal and cAMP-inducible expression in type II cells. We also observed that there were no obvious differences in the magnitude of the responses of these fusion genes to cAMP treatment.

The gene encoding surfactant protein A (SP-A) is expressed in type II pneumonocytes and is developmentally and hormonally regulated in fetal lung tissue. SP-A is encoded by a single-copy gene in rabbits, dogs, rats, and mice. By contrast, the human genome contains two similar genes, hSP-A1 and hSP-A2, which are differentially regulated during development and differentially regulated by adenosine 3',5'-cyclic monophosphate (cAMP) and glucocorticoid treatment of human fetal lung in culture. In the present study, we have isolated and characterized baboon genomic clones containing two highly similar SP-A genes. Restriction mapping of these clones, together with Southern analysis of genomic DNA, indicates that these comprise two distinct baboon SP-A genes. Sequence comparison of DNA upstream of the transcription initiation sites and within the 3'-untranslated regions encoded by exon VI indicates that one of the baboon SP-A genes (bSP-A1) is more similar to hSP-A1, whereas the other (bSP-A2) is more similar to hSP-A2. Primer extension analysis of baboon lung mRNA indicates that both baboon SP-A genes utilize conserved transcription initiation sites. Reverse transcriptase-polymerase chain reaction analysis of RNA isolated from lung tissues of fetal baboons of 160 days gestational age indicates that both bSP-A1 and bSP-A2 are expressed in baboon fetal lung and that mRNA transcripts of bSP-A1 and bSP-A2 genes are primarily comprised of sequences encoded by exons I and III-VI. However, minor transcripts of the bSP-A1 gene containing exon II and exon II plus an extension also were detected. The presence of two SP-A genes in the baboon suggests that duplication of the SP-A gene occurred > 26.5 million years ago, before divergence of the baboon lineage from the man-gorilla-chimpanzee clade.

No abstract

The gene encoding surfactant protein (SP) A, a developmentally regulated pulmonary surfactant-associated protein, is expressed in a lung-specific manner, primarily in pulmonary type II cells. SP-A gene transcription in the rabbit fetal lung is increased by cAMP. To delineate the genomic regions involved in regulation of SP-A gene expression, lines of transgenic mice carrying fusion genes composed of various amounts of 5′-flanking DNA from the rabbit SP-A gene linked to the human growth hormone structural gene as a reporter were established. We found that as little as 378 bp of 5′-flanking DNA was sufficient to direct appropriate lung cell-selective and developmental regulation of transgene expression. The same region was also sufficient to mediate cAMP induction of transgene expression. Mutagenesis or deletion of either of two DNA elements, proximal binding element and a cAMP response element-like sequence, previously found to be crucial for cAMP induction of SP-A promoter activity in transfected type II cells, did not affect lung-selective or temporal regulation of expression of the transgene; however, overall levels of fusion gene expression were reduced compared with those of wild-type transgenes.