Mammaglobin is found in breast tissue as a complex with BU101.

The mammaglobin gene has been shown to be preferentially expressed in breast tissue. Few genes match its specificity. Mammaglobin has generated much interest, and studies are ongoing to develop diagnostic tests for breast cancer based on the detection of mammaglobin. While searching the Incyte Genomics Lifeseq database for tissue-specific markers, we observed a second secretoglobin, BU101, also known as lipophilin B. We report here that mammaglobin, in breast tissue, is found as a complex with BU101. The complex was isolated from breast cancer tissue and was characterized as the biologically relevant form of mammaglobin.

Methylated poly(L-lysine): conformational effects and interactions with polynucleotides.

Methylated lysine, arginine and histidine residues are found in a number of proteins (for example, histones, non-histone chromosomal proteins, ribosomal proteins, calmodulin, cytochrome C, etc.). We are studying the effects of methylation on the conformations of poly(lysine) and of the effects of methylation of poly(lysine) and poly(arginine) on interactions with polynucleotides. The conformational properties of epsilon-amino-methylated poly(lysine) differ from those of unmodified poly(lysine). Methylation increases resistance to thermally-induced and NaCl-induced changes in the CD spectrum. Guanidinium chloride increases (proportional to the degree of methylation) the extent of approach to the conformation in dispute as to its being a random coil or an extended helix. Methylation enhances aggregation in the helix-inducing solvent 0.5 M Ca(ClO4)2. With increasing methylation of poly(lysine), the conformation in dodecyl sulfate changes from beta, to 50% alpha, to random coil at the maximum methylation. Increasing methylation of poly(lysine) weakens the interaction with polynucleotides in respect to dissociation by salt, linearly with methyl content. Complexes of (dAdT)n.(dAdT)n with the polypeptides are increasingly stabilized to heat denaturation by progressive methylation. However, with a series of synthetic double-stranded RNA's and DNA's a more complex situation exists, Tm increasing or decreasing, depending on the base composition, sequence and type of sugar. Methylation of poly(lysine) and poly(arginine) can have opposite effects on Tm based on results with complexes with (dI)n.(dC)n. Methylated poly(lysine) affects the CD spectrum of polynucleotides, in a manner dependent on base composition and sequence. In some cases large positive or negative psi-spectra are induced, which, in the case of (dGdC)n.(dGdC)n, can be positive or negative depending on the degree of methylation of the polypeptide and the salt concentration. It is suggested that the biological effects of methylation proteins may be evoke by salt changes in the cell cycle, and that methylation can affect local interactions with nucleic acids and larger scale structure, and interactions with lipids.

Human serum digests poly(rI) X poly(rC) differently from other mammalian sera.

Using a new spectrophotometric assay, we found that human serum digests predominately (rC)n of (rI)n X (rC)n, in agreement with results of Nordlund et al. (Proc. Soc. Exp. Biol. Med., 1970, 133, 439-444) and DeClercq (Eur. J. Biochem., 1979, 93, 165-172) while rhesus monkey, cat, and rabbit sera digest primarily (rI)n. The results of Nordlund et al. also show (in agreement with our results) that human serum digests more of the (rC)n strand of (rI)n X (rC)n than rabbit serum. However, their results differ from ours, since they found that rabbit serum digests nearly equal, but small amounts of (rI)n and (rC)n. Results are discussed in relation to interferon (IFN) induction and toxicity following administration of (rI)n X (rC)n.

Poly ICLC induces anti-IC antibodies in mice and rabbits.

Poly ICLC is an interferon (IFN) inducer and antiviral, antitumor, radioprotective, and immunoregulatory agent. We show that administration of poly ICLC to mice and rabbits also results in the presence of anti-IC antibodies in their serum.

Poly ICL-CM dextran: an interferon inducer of reduced toxicity.

We have prepared soluble complexes of poly ICL-CM dextran that are as effective interferon IFN inducers, in mice and in rhesus monkeys, as poly ICLC. Toxicity testing was carried out in mice and, poly ICL-CM dextran is less toxic, in mice, than poly ICLC is.

Interactions of poly (N epsilon , N epsilon , N epsilon ,-trimethyllysine) and poly(lysine) with polynucleotides: circular dichroism and A-T sequence selectivity.

Complexes of (Lys) and [Lys(Me3)]n with natural and synthetic DNAs have been studied by CD as a function of ionic strength. In dilute EDTA, (Lys)n and [Lys(Me3)]n produce the same distortions to the CD spectrum of calf thymus DNA at r (peptide residue/nucleotide residue) values less than 0.6. At higher r values, the distortions are somewhat different. [Lys(me3)]n alters the conformation of some polynucleotides differently from (Lys)n under non- psi conditions. Therefore, methylation of histones may serve to alter the structure of chromatin. At low ionic strength, [Lys(Me3)]n and (Lys)n alter the viscosity of DNA to the same extent between r values of 0.0 and 1.0. In contrast to (Lys)n-DNA, at high ionic strengths, [lys(Me3)]n-DNA does not show psi - type CD spectra. (Lys)n forms psi - structures with (dA-dT)n and (dG-dC)n. [Lys(Me3)]n forms psi + structures with (dA-dT)n. Between 0.05 and 0.3 M NaCl, [Lys(Me3)]n forms psi+ structures with (dG-dC)n, while between 0.35 and 0.45 M NaCl, it forms a psi - structure with (dG-dC)n. Neither (Lys)n nor [Lys(Me3)]n forms psi structures with (dA)n.(dT)n or (dG)n.(dC)n. These results, in conjunction with the work of others on reconstitution of nucleosome-like particles from synthetic polynucleotides, suggest that the ability of DNA and histones to form nucleosomes is related to the formation of psi structures. (Lys)n binds preferentially to (dA)n.(dT)n over (dA-dT)n. [Lys(Me3)]n binds to (dA)n.(dT)n and (dA-dT)n with equal affinity.

Interactions of poly(N epsilon, N epsilon, N epsilon-trimethyllysine) and poly(N delta, N delta, N delta-trimethylornithine) with polynucleotides: salt dissociation and thermal denaturation.

The interaction of poly(N epsilon, N epsilon, N epsilon-trimethyl-L-lysine) ([Lys(Me3)]n) and poly(N delta, N delta, N delta-trimethyl-L-ornithine) ([Orn(Me3)]n) with polynucleotides was studied by thermal denaturation, viscosity, and dissociation by salt. The methylated polymers decrease the viscosity of DNA in proportion to the amount of bound peptide. [Lys(Me3)]n and [Orn(Me3)]n raise Tm of polynucleotides more than do (Lys)n and (Orn)n. Dissociation of the polypeptide-polynucleotide complexes with NaCl, KCl, or MgCl2 required about half the salt concentration for the methylated polymers as for the parent polymers. The effects of Tm on DNA appear to be complex and may involve differences in the hydrophobic effects, solvation, and conformational entropy. The salt dissociation data are discussed in relation t the role of histone methylation in chromatin function.