Sp Genes Research Articles

Two juvenile hormone suppressible storage proteins may play different roles in Hyphantria cunea Drury.

We isolated and sequenced cDNA clones corresponding to two storage proteins (HcSP-1 and HcSP-2) from fall webworm, Hyphantria cunea. The cDNAs for HcSP-1 (2,337 bp) and HcSP-2 (2,572 bp) code for 753 and 747 residue proteins with predicted molecular masses of 88.3 and 88.5 kDa, respectively. The calculated isoelectric points are pI = 8.4 (HcSP-1) and 7.6 (HcSP-2). Multiple alignment analysis of the amino acid sequence revealed that HcSP-1 is most similar to SL-1 from S. litura (73.8% identity) and other methionine-rich hexamers, whereas HcSP-2 is most similar to the SL-2 alpha subunit from S. litura (74.8% identity) and other moderately methionine-rich hexamers. The two storage proteins from H. cunea shared only 38.4% identity with one another. According to both phylogenetic analyses and the criteria of amino acid composition, HcSP-1 belongs to the subfamily of Met-rich storage proteins (6% methionine, 10% aromatic amino acid), and HcSP-2 belongs to the subfamily of moderately methionine-rich storage proteins (3.2% methionine, 12.9% aromatic amino acid). Topical application of the JH analog, methoprene, after head ligation of larvae, suppressed transcription of the SP genes, indicating hormonal effects at the transcriptional level. The HcSP-1 transcript was detected by Northern blot analysis in Malpighian tubule, testis, and ovary, in addition to fat body where it was most abundant. The HcSP-2 transcript was detected only in fat body and Malpighian tubule. The accumulation of HcSP-1 in ovary and HcSP-2 in Malpighian tubule might be related to differential functions in both organs.

Developmental and Glucocorticoid Regulation of Surfactant Protein mRNAs in Fetal Sheep † 310

We previously found that glucocorticoid treatment of pregnant sheep increases the content of surfactant proteins SP-A and SP-B in lung tissue and lavage of preterm lambs. To investigate the mechanism of this induction process, we quantitated SP mRNA levels after administration of betamethasone(0.5 mg/kg) to pregnant sheep prior to premature delivery of the fetus at 125 days. In the first protocol, 55 sheep were injected weekly with 1-4 doses of either saline (control) or betamethasone beginning at 104 days gestation with the last dose given 24 h prior to delivery. In a second protocol, 39 sheep were injected with 1-2 doses of saline or betamethasone at 24 and 48 h prior to delivery. Total RNA was extracted from fetal lung and hybridized with cDNAs for sheep SP-A, SP-B and SP-C and human β-actin. mRNA levels for control preterm lambs were 21%, 28% and 39% of the level in term lambs for SP-A, -B and -C, respectively. No increases in mRNA levels were demonstrated in sheep given 1-3 weekly doses of betamethasone vs. control. However, 4 doses of betamethasone, as well as both 48h treatment regimens, produced a 2- to 3-fold increase in each SP mRNA (p<0.01 by ANOVA), achieving levels equivalent to 60-75% of term control lambs. The magnitude of the betamethasone-induced increase in SP mRNA is similar to that for tissue SP-A and SP-B after 2-4 betamethasone doses. The observation that SP-A and SP-B proteins are increased 2 wk after betamethasone treatment, whereas mRNAs are not, implies that induction occurs with 2 doses, is reversible, and that the proteins have a longer half-life than the mRNAs. We conclude that in vivo betamethasone treatment rapidly induces a maximal and coordinated increase in SP-A, SP-B, and SP-C mRNAs which is fully reversible within 7 days. Similar increases in SP mRNA and protein content confirm that glucocorticoid regulation of SP genes in vivo is largely transcriptional.

Assignment1 of Sp genes to rat chromosome bands 7q36 (Sp1), 10q31→q32.1 (Sp2), 3q24→q31 (Sp3) and 6q33 (Sp4) and of the SP2 gene to human chromosome bands 17q21.3→q22 by in situ hybridization

Assignment1 of Sp genes to rat chromosome bands 7q36 (Sp1), 10q31→q32.1 (Sp2), 3q24→q31 (Sp3) and 6q33 (Sp4) and of the SP2 gene to human chromosome bands 17q21.3→q22 by in situ hybridization

Inheritance of the spangled plumage pattern and the marbled chick down phenotypes of the silver‐spangled Hamburgh Bantam

Abstract 1. An investigation was conducted among the progeny from crosses between Silver‐Spangled and Gold‐Pencilled Hamburgh bantams, and between Silver‐Spangled Hamburgh and Double‐Laced Barnevelder bantams. 2. Two subjects were studied: the relationship between three plumage pattern phenotypes, spangling, transverse‐barring and double‐lacing, all of which are arrangements of eumelanin expressed on a background of phaeomelanic pigmentation and the inheritance of the marbled chick down of the Silver‐Spangled Hamburgh bantam. 3. Examination of the F2 generations demonstrated that, in conjunction with silver (S) gene(s) and extended black (E) alleles at the E‐locus the silver‐spangled phenotype can be produced by the addition to the genotypes of the Gold‐Pencilled Hamburgh, homozygous ebc (Db‐ml+‐Pg), and Double‐Laced Barnevelder, homozygous eb (db+‐Ml‐Pg), of Sp and Db genes respectively. Consequently Sp and Ml are one and the same gene, for which I retain the symbol Ml, and the genotype of the Silver‐Spa...

The yeast acid phosphatase can enter the secretory pathway without its N-terminal signal sequence.

The repressible Saccharomyces cerevisiae acid phosphatase (APase) coded by the PHO5 gene is a cell wall glycoprotein that follows the yeast secretory pathway. We used in vitro mutagenesis to construct a deletion (delta SP) including the entire signal sequence and four amino acids of the mature sequence of APase. An APase-deficient yeast strain was transformed with a high-copy-number plasmid carrying the PHO5/delta SP gene. When expressed in vivo, the PHO5/delta SP gene product accumulated predominantly as an inactive, unglycosylated form located inside the cell. A large part of this unglycosylated precursor underwent proteolytic degradation, but up to 30% of it was translocated, core glycosylated, and matured by the addition of mannose residues, before reaching the cell wall. It appears, therefore, that the signal sequence is important for efficient translocation and core glycosylation of yeast APase but that it is not absolutely necessary for entry of the protein into the yeast secretory pathway. mRNA obtained by in vitro transcription of PHO5 and PHO5/delta SP genes were translated in vitro in the presence of either reticulocyte lysate and dog pancreatic microsomes or yeast lysate and yeast microsomes. The PHO5 gene product was translocated and core glycosylated in the heterologous system and less efficiently in the homologous system. We were not able to detect any translocation or glycosylation of PHO5/delta SP gene product in the heterologous system, but a very small amount of core suppression of glycosylated material could be evidenced in the homologous system.

The yeast acid phosphatase can enter the secretory pathway without its N-terminal signal sequence.

The repressible Saccharomyces cerevisiae acid phosphatase (APase) coded by the PHO5 gene is a cell wall glycoprotein that follows the yeast secretory pathway. We used in vitro mutagenesis to construct a deletion (delta SP) including the entire signal sequence and four amino acids of the mature sequence of APase. An APase-deficient yeast strain was transformed with a high-copy-number plasmid carrying the PHO5/delta SP gene. When expressed in vivo, the PHO5/delta SP gene product accumulated predominantly as an inactive, unglycosylated form located inside the cell. A large part of this unglycosylated precursor underwent proteolytic degradation, but up to 30% of it was translocated, core glycosylated, and matured by the addition of mannose residues, before reaching the cell wall. It appears, therefore, that the signal sequence is important for efficient translocation and core glycosylation of yeast APase but that it is not absolutely necessary for entry of the protein into the yeast secretory pathway. mRNA obtained by in vitro transcription of PHO5 and PHO5/delta SP genes were translated in vitro in the presence of either reticulocyte lysate and dog pancreatic microsomes or yeast lysate and yeast microsomes. The PHO5 gene product was translocated and core glycosylated in the heterologous system and less efficiently in the homologous system. We were not able to detect any translocation or glycosylation of PHO5/delta SP gene product in the heterologous system, but a very small amount of core suppression of glycosylated material could be evidenced in the homologous system.

A hybrid recognition sequence in a recombinant restriction enzyme and the evolution of DNA sequence specificity.

Early attempts to generate new restriction specificities by recombination between allelic restriction-modification systems have been unsuccessful. Bullas et al. succeeded in isolating a new specificity, SQ, in Salmonella that they interpreted as being the result of a recombination event between the parental strains, Salmonella typhimurium and S. postdam, which encode the SB and SP restriction systems, respectively. This interpretation has recently been confirmed by DNA heteroduplex studies with the SB, SP and SQ structural genes. We have determined the DNA sequences recognized by the SB and SP enzymes and found that, like all type I restriction sequences, they are split into two specific domains by a spacer of nonspecific sequence that, for both SB and SP, is 6 base pairs (bp) long. We have now determined the sequence recognized by the recombinant SQ enzyme and find that it is a hybrid between the SB and SP sequences, containing one specific domain from each parental strain. This result implies that each of the two specific domains is recognized by a physically distinct part of the enzyme.