TY - JOUR
T1 - Differential regulation of baboon SP-A1 and SP-A2 genes
T2 - Structural and functional analysis of 5'-flanking dna
AU - Li, Jinxing
AU - Gao, Erwei
AU - Seidner, Steven R.
AU - Mendelson, Carole R.
PY - 1998
Y1 - 1998
N2 - 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-A genes 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.
AB - 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-A genes 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.
KW - Deoxyribonucleic acid
KW - Fetal lung
KW - Ribonuclease protection assay
KW - Surfactant protein A
KW - Thyroid transcription factor-1
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U2 - 10.1152/ajplung.1998.275.6.l1078
DO - 10.1152/ajplung.1998.275.6.l1078
M3 - Article
C2 - 9843844
AN - SCOPUS:0032441936
SN - 1040-0605
VL - 275
SP - L1078-L1088
JO - American Journal of Physiology
JF - American Journal of Physiology
IS - 6 19-6
ER -