Molecular cloning, sequence analysis, expression, and tissue distribution of suppressin, a novel suppressor of cell cycle entry.

Suppressin (SPN) is an inhibitor of cell proliferation that was originally identified and purified to homogeneity from bovine pituitaries (LeBoeuf, R. D., Burns, J. N., Bost, K. L., and Blalock, J. E. (1990) J. Biol. Chem. 265, 158-165). In this report we have cloned the full-length cDNA encoding rat SPN and have identified the tissue distribution of SPN expression. The cDNA of SPN is 1882 nucleotides with a 1488-base coding region and 55 and 339 nucleotides of 5'- and 3'-untranslated sequences, respectively. Northern gel analysis of rat pituitary mRNA showed a single hybridizing species at approximately 2 kilobases. Sequence analyses showed that the nucleotide and deduced amino acid sequences of SPN are novel and unrelated to any known vertebrate inhibitors of proliferation. However, the deduced amino acid sequence of SPN contains two domains that have extensive sequence identity with a recently cloned transcription activator in Drosophila, deformed epidermal autoregulatory factor-1 (DEAF-1, see Gross, C. T., and McGinnis, W. (1996) EMBO J. 15, 1961-1970) suggesting that SPN represents a vertebrate cognate of deformed epidermal autoregulatory factor-1. Reverse transcriptase-polymerase chain reaction and immunohistochemical analyses showed that the SPN mRNA and the SPN protein are expressed in every tissue examined including testis, spleen, skeletal muscle, liver, kidney, heart, and brain suggesting that SPN may be involved in the control of proliferation in a variety of cell types.

Animal carotenoids 15. Carotenoid distribution and carotenoprotein of Asterias rubens.

A clear differentiation in localization according to functional groups in the carotenoids of the starfish, Asterias rubens, is reported. Only the free alpha-ketols, 7,8,7',8'-tetradehydroastaxanthin, 7,8-didehydroastaxanthin and astaxanthin, are present in the purified carotenoprotein. A post mortem liberated slime contained beta,beta-carotene, free and esterified alloxanthin and esterified alpha-ketols. Evidence suggesting the existence of an alloxanthin protein complex was obtained. The carotenoprotein, asteriarubin, accounts for approx. 10% of the protein extracted by low salt dialysis from the purple-blue part of the top skin of A. rubens and exhibits an absorbance maximum at 554 nm in buffer solution. Asteriarubin is a glycoprotein with an equivalent Stoke's radius corresponding to that of globular proteins of molecular weight 8--10 10(4) and contains 20 microgram carotenoid per mg asteriarubin. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of purified asteriarubin disclosed two major components, one of which is a glycopeptide.