Predicting nose projection and pronasale position in facial approximation: a test of published methods and proposal of new guidelines

Many prediction guidelines exist in facial approximation for determining the soft-tissue features of the face, and the reliability of each is generally unknown. This study examines four published and commonly used soft-tissue prediction guidelines for estimating nose projection, two of which also estimate the position of the pronasale. The methods tested are those described by: 1) Gerasimov ([1971] The Face Finder; London: Hutchinson & Co.), using the distal third of the nasal bones and the nasal spine; 2) Krogman ([1962] The Human Skeleton in Forensic Medicine; Springfield: Charles C. Thomas), using the average soft-tissue depth at midphiltrum, plus three times the length of the nasal spine (and a variation of this technique: plus three times the distance of the tip of the nasal spine from the nasal aperture); 3) Prokopec and Ubelaker ([2002] Forensic Sci Commun 4:1-4), using the reflected profile line of the nasal aperture; and 4) George ([1987] J Forensic Sci 32:1305-1330), using a variation of the Goode method. Four identical hard-tissue tracings were made of 59 adult lateral head cephlograms (29 males, mean age 24, SD 10 years; 30 females, mean age 23, SD 5 years) on separate sheets of tracing paper. One soft-tissue tracing was also made for each radiograph. All tracings were marked with three identical reference points. Soft-tissue tracings were isolated from one of us (C.N.S.), who attempted under blind conditions to predict pronasale position and nose projection on the hard-tissue tracings, using the soft-tissue prediction guides above. Actual soft-tissue tracings were then compared to each of the predicted tracings, and differences in projection/pronasale position were measured. Results indicate that for nose projection, methods 3 and 4 performed well, while methods 1 and 2 performed poorly. Features which are most related to nose projection/pronasale are described in this paper, as are regression equations generated from these variables that predict pronasale/nose projection better than the traditional methods mentioned above. The results of this study are significant because they: 1) indicate that the popular facial approximation methods used to build the nose are inaccurate and produce incorrect nose anatomy; and 2) indicate that the new pronasale prediction methods developed here appear to have less error than traditional methods.     

Test of the Lamendin aging method on two historic skeletal samples

The Lamendin aging method involves the quantification of root translucency and the attachment position of the periodontal membrane. It was developed using recent medical-examiner specimens, and was tested on modern skeletal samples such as the Terry Collection (Lamendin et al. [1992] J. Forensic Sci. 37:1373-1379; Prince and Ubelaker [2002] J. Forensic Sci. 47:107-116). The method may be one of the most useful for estimating age after the mid-30s. The current study is an evaluation of the Lamendin criteria on two historic skeletal samples from Britain. Both the Christ's Church Spitalfields and St. Bride's Church collections represent documented skeletal samples that were interred in the 18th and 19th centuries. In total, 1,188 teeth from 220 adult individuals were examined from these two collections. The Lamendin method requires measuring total root length (cementoenamel junction to apex), gingival regression (cementoenamel junction to periodontal ligament attachment), and root translucency (root apex to maximum level of root translucency) on the labial surface of single-rooted teeth. Our results indicate that postmortem factors affect the applicability of the Lamendin technique to archaeological and historical samples. In particular, root translucency disappears with time, or is obscured by unknown postmortem taphonomic effects related to the length of interment or postmortem environment. Thirty-five percent of our sample showed no root translucency, indicating that caution is required when applying this method to archaeological or historical remains. The mean error of age estimates for Spitalfields and St. Bride's was higher than in the original study of Lamendin et al. ([1992] J. Forensic Sci. 37: 1373-1379), and higher than in the test by Prince and Ubelaker ([2002] J. Forensic Sci. 47:107-116) of the Lamendin method on the Terry Collection.     

Craniofacial anthropometry: Practical measurements of the head and face for clinical,surgical and research use.

By J.C. Kolar and E.M. Salter. Springfield, IL: Charles C. Thomas. 1996. xxiii + 334 pp. ISBN 0-398-06616-7. $69.95 (cloth).     

4 Steps toward Inquiry Centered Teaching

Stidworthy, John. Life Begins. The Day of the Dinosaurs. Mighty Mammals of the Past. When Humans Began. Morristown, N.J.: Silver Burdett Co., 1986. Each 37 pp. $6.75 softcover Reveiwed by Donald J. Nash

McKay, David W., and Bruce G. Smith Space Science Projects for Young Scientists (Projects for Young Scientists series). New York: Franklin Watts, 1986. 127 pp. $ 10.90 hardcover (school and library binding) Reveiwed by Robert G. Hoehn

Griffin, Robert D. The Biology Coloring Book. Diamand, M. C., et al. The Human Brain Coloring Book. New York: Harper &; Row, 1986. Ill pp. (Biology) and 281 pp. (Brain) $9.95 paper

Kallenbach, Ernst. The Light Microscope: Principles and Practice for Biologists. Springfield, Il.: Charles C. Thomas, 1986. 56 pp. $14.25 softcover. Reveiwed by Robert E. Knowlton     

Analysis of quantitative methods for rib seriation using the Spitalfields documented skeletal collection

Accurate rib seriation is essential in forensic anthropology and bioarchaeology for determination of minimum numbers of individuals, sequencing trauma patterns to the chest, and identification of central ribs for use in age estimation. We investigate quantitative methods for rib seriation based on three metric variables: superior (anterior) costo-transverse crest height (SCTCH), articular facet of the tubercle-to-angle length (AFTAL), and head-to-articular facet length (HAFL). The sample consists of complete but unseriated sets of ribs from 133 individuals from the documented (known age and sex) and undocumented skeletal collections of Christ Church Spitalfields, London. This research confirms the results of an earlier study (Hoppa and Saunders [1998] J. Forensic. Sci. 43:174-177) and extends it with the application of two new metric traits and further analyses of sex differences. Analyses of variance showed that SCTCH and AFTAL are significantly associated (P < 0.001) with rib number. Tukey tests of pairwise rib comparisons revealed that for two dimensions (SCTCH and AFTAL), the central ribs (3rd-6th) are significantly distinct from each other (P < 0.05). Using simple ranking of either the SCTCH or AFTAL traits, the proportion of correctly identified ribs within +/-1 position was 80%, compared to initial seriation using morphological methods (Dudar [1993] J. Forensic. Sci. 28:788-797; Mann [1993] J. Forensic. Sci. 28:151-155). Significant sex dimorphism was also identified for these two traits. Analysis of the HAFL trait produced somewhat equivocal results, suggesting that this variable is not reliable for rib seriation. The variable SCTCH proves to be the most useful dimension for seriation, and shows that all but the 7th-9th ribs can be distinguished from others in the sequence, with important results for the 4th rib, where ranking allowed identification in 86% of cases, consistent with morphological methods for intact ribs.     

Sexing potential of fragmentary and pathological metacarpals

The use of metacarpal dimensions for determining skeletal sex is investigated. Previous studies on sexual dimorphism in the metacarpals (Scheuer and Elkington [1993]; J. Forensic Sci. 38:769–778; Falsetti [1995]; J. Forensic Sci. 40:774–776; Smith [1996]; J. Forensic Sci. 41:469–477) used multiple variables, which limits the application potential of the methodology. Using six measurements for each metacarpal, I generated 35 linear discriminant functions based on expected taphonomic or pathological preservation scenarios. The number of variables per function ranged from 2–5. Normal, jackknifed, and cross-validation classification matrices indicated a sex prediction accuracy in the 79–85% range. MC4 produced the most consistent functions. Overall accuracy in the validation samples ranged from 75–90%. ANOVA and MANOVA analyses indicated that population effects are insignificant, which may allow for the application of the functions without knowledge of the ancestral background of the individual. This, combined with the variety of preservation scenarios considered, provides accurate sex estimators for incomplete individuals. However, the population specificity of the insignificant population group effects remains untested. Am J Phys Anthropol 109:245–252, 1999. © 1999 Wiley-Liss, Inc.     

Voltage-dependent gap junction channels are formed by connexin32, the major gap junction protein of rat liver.

We report here experiments undertaken in pairs of hepatocytes that demonstrate a marked voltage sensivity of junctional conductance and, thus, contradict earlier findings reported by this laboratory (Spray, D.C., R.D.ginzberg, E.A., E. A. Morales, Z. Gatmaitan and I.M. Arias, 1986, J. Cell Biol. 101:135-144; Spray C.D. R.L. White, A.C. Campos de Carvalho, and M.V.L. Bennett. 1984. Biophys. J. 45:219-230) and by others (Dahl, G., T. Moller, D. Paul, R. Voellmy, and R. Werner. 1987. Science [Wash. DC] 236:1290-1293; Riverdin, E.C., and R. Weingart. 1988. Am. J. Physiol. 254:C226-C234). Expression in exogenous systems, lipid bilayers in which fragments of isolated gap junction membranes were incorporated (Young, J.D.-E., Z. Cohn, and N.B. Gilula. 1987. Cell. 48:733-743.) and noncommunicating cells transfected with connexin32 cDNA (Eghbali, B., J.A. Kessler, and D.C. Spray. 1990. Proc. Natl. Acad. Sci. USA. 87:1328-1331), support these findings and indicate that the voltage-dependent channel is composed of connexin32, the major gap junction protein of rat liver (Paul, D. 1986. J. Cell Biol. 103:123-134).     

A study of the electron paramagnetic resonance properties of single monoclinic crystals of bovine superoxide dismutase

Monoclinic crystals of native bovine superoxide dismutase and its monocyano derivative were studied by means of electron paramagnetic resonance spectroscopy. Through computer simulation of the spectra, the directions of the principal axes of the magnetic tensors (g and A) have been found with respect to the crystal principal axes and with respect to the positions of atoms bear the Cu(II) as previously determined by x-ray crystallography (Richardson, J. S., Thomas, K. A., and Richardson, D. C. (1975) Biochem. Biophys. Res. Commun. 63, 986-992; Tainer, J. A., Getzoff, E. D., Richardson, J. S., and Richardson, D. C. (1980) in 2SOD: Cu, Zn-Superoxide Dismutase Complete Atomic Coordinates (Richardson, D. C., and Richardson, J. S., eds) Brookhaven Protein Structure Data Bank). In the native protein, the direction of the gz axis of Cu(II) was found to lie perpendicular to the rough plane formed by the four imidazole nitrogen atoms coordinated to the Cu(II). The direction of gy is approximately along the His 44N-Cu-His 46N direction, and gx is in the direction of the Cu-His 61-Cu-N bond. The A is coaxial with g within 15 degrees C. A substantial shift occurs in the direction of gz when CN- binds to the Cu(II), suggesting a change in the coordination configuration of the metal.     

The medical complaints of the relatives of the psychotic,the alcoholic and the epileptic

EXPANDING GOALS OF GENETICS IN PSYCHIATRY: Franz J. Kallmann, Editor. Grune &; Stratton, New York, 1962. 275 pp., $6.75.

PHARMACOGENETICS. HEREDITY AND THE RESPONSE TO DRUGS: Werner Kalow. W. B. Saunders Company, Philadelphia, 1962. vi + 231 pp. $8.00.

POSTWAR POPULATION TRANSFERS, 1945–1955: Joseph B. Schechtman. University of Pennsylvania Press, Philadelphia, 1962. 417 pp., $6.00.)

MENTAL HEALTH IN THE METROPOLIS: THE MIDTOWN MANHATTAN STUDY, VOLUME I: Leo Srole, Thomas S. Lang‐ner, Stanley T. Michael, Marvin K. Opler, and Thomas A. C. Rennie. McGraw‐Hill, New York, 1962. 428 pp., $9.95.     

The association of prosomes with some of the intermediate filament networks of the animal cell [published erratum appears in J Cell Biol 1989 Mar;108(3):following 1175]

The small RNP complexes of defined morphology and biochemical composition termed prosomes, first isolated from the cytoplasm associated with repressed mRNA (Martins de Sa, C., M.-F. Grossi de Sa, O. Akhayat, F. Broders, and K. Scherrer. J. Mol. Biol. 1986. 187:47-493), were found also in the nucleus (Grossi de Sa, M.-F., C. Martins de Sa, F. Harper, O. Coux, O. Akhayat, P. Gounon, J. K. Pal, Y. Florentin, and K. Scherrer. 1988. J. Cell Sci. 89:151-165). Immunofluorescence, immunoelectron microscopy, and immunochemical studies using mAbs directed against some of the prosomal proteins of duck erythroblasts indicate that in the cytoplasm of HeLa and PtK cells, prosome antigens are associated with the intermediate filament network of the cytokeratin type.     

Accuracy of dental age estimation charts: Schour and Massler,Ubelaker and the London Atlas

Dental age estimation charts are frequently used to assess maturity and estimate age. The aim of this study was to assess the accuracy of estimating age of three dental development charts (Schour and Massler, Ubelaker, and the London Atlas). The test sample was skeletal remains and dental radiographs of known‐age individuals (N = 1,506, prenatal to 23.94 years). Dental age was estimated using charts of Schour and Massler, Ubelaker, and The London Atlas. Dental and chronological ages were compared using a paired t‐test for the three methods. The absolute mean difference between dental and chronological age was calculated. Results show that all three methods under‐estimated age but the London Atlas performed better than Schour and Massler and Ubelaker in all measures. The mean difference for Schour and Massler and Ubelaker was ?0.76 and ?0.80 years (SD 1.27 year, N = 1,227) respectively and for the London Atlas was ?0.10 year (SD 0.97 year, N = 1,429). Further analysis by age category showed similar accuracy for all three methods for individuals younger than 1 year. For ages 1–18, the mean difference between dental and chronological ages was significant (P < 0.05) for Schour and Massler and Ubelaker and not significant (P > 0.05) for the London Atlas for most age categories. These findings show that the London Atlas performs better than Schour and Massler and Ubelaker and represents a substantial improvement in accuracy of dental age estimation from developing teeth. Am J Phys Anthropol 154:70–78, 2014. © 2014 Wiley Periodicals, Inc.     

Identification of porins in the outer membrane of Pseudomonas aeruginosa that form small diffusion pores

The purified outer membrane proteins of Pseudomonas aeruginosa were reconstituted with phosphatidylcholine and dicetylphosphate into membrane vesicles, and these were tested by the liposome swelling method for the diffusion of saccharides with different Mr. Proteins C (Mr, 70,000), D (Mr, 46,000), and E (Mr, 43,000) were found to confer the monosaccharide-permeable pores in the reconstituted liposome membranes. The membrane vesicles containing proteins F (Mr, 34,000), G (Mr, 25,000), or H (Mr, 19,000) showed no detectable pore-forming activity. The pores formed by proteins C, D, or E appeared to be smaller than that formed by the Escherichia coli porins. The size of the solutes that permeated through the newly identified porins is similar to that through the intact and purified outer membrane of P. aeruginosa (Yoneyama, H., and Nakae, T. (1986) Eur. J. Biochem. 157, 33-38; Yoshihara, E., Gotoh, N., and Nakae, T. (1988) Biochem. Biophys. Res. Commun. 156, 470-476).     

Dexamethasone does not interfere with hormone-sensitive PI hydrolysis

Serum, but not epidermal growth factor (EGF), stimulated the release of radiolabeled inositol phosphates from human embryo palate mesenchyme (HEPM) cells prelabeled with [3H]-myoinositol. Pretreatment of cells with 10(-6) M dexamethasone (DEX) for 48 h had no effect on the release of inositol phosphates in response to serum. Furthermore, although treatment of the glucocorticoid-sensitive A/J strain of mouse embryo palate mesenchyme (MEPM) cells with 10(-6) M DEX inhibited their proliferation by 40%, it had no effect on the activity of phospholipase(s) C. However, DEX did enhance the incorporation of [3H]-myoinositol into membrane lipids. We interpret these data to mean that 1) serum factors enhance metabolism of inositol lipids in HEPM cells, 2) DEX does not interfere with the primary events by which agonists utilize metabolism of inositol lipids as a mechanism for transmembrane signaling, and 3) DEX may affect synthesis of phosphoinositides, as reported by Grove et al. (Biochem. Biophys. Res. Commun. 110:200-207, 1983; J. Craniofac. Genet. Dev. Biol. Suppl. 2:285-292, 1986).     

Book reviews

Book reviews in This Article:
Detection of Bacterial Endotoxins with the limulus amebocyte lysate Test (1987). Edited by Stanley W. Watson, Jack Levin & Thomas J. Novitsky.
Computers in Microbiology (1987). Edited by J.D. Rant, R.K.A. Feltham & W. Shepherd.
Molecular Strategies of Parasite Invasion (1987). Edited by N. Agabian, H. Goodman & N. Nogueira.
Footrot in Ruminants (1986). Edited by D.J. Stewart, J.E. Peterson, N.M. McKern & D.L.
Bacterial Protein Toxins (1986). Edited by P. Falmagne, J.E. Alouf, F.J. Fehrenbach, J. Jeljaszewicz & M. Thelestam.
Carbon Substrates in Biotechnology (1987). Edited by J.D. Stowell, A.J. Beardsmore, C.W. Keevil & J.R. Woodward.     

Constitutive and UV-mediated activation of RecA protein: combined effects of recA441 and recF143 mutations and of addition of nucleosides and adenine.

The recF143 mutant of Escherichia coli is deficient in certain functions that also require the RecA protein: cell survival after DNA damage, some pathways of genetic recombination, and induction of SOS genes and temperate bacteriophage through cleavage of the LexA and phage repressors. To characterize the role of RecF in SOS induction and RecA activation, we determined the effects of the recF143 mutation on the rate of RecA-promoted cleavage of LexA, the repressor of the SOS genes. We show that RecA activation following UV irradiation is delayed by recF143 and that RecF is specifically involved in the SOS induction pathway that requires DNA replication. At 32 degrees C, the recA441 mutation partially suppresses the defect of recF mutants in inducing the SOS system in response to UV irradiation (A. Thomas and R. G. Lloyd, J. Gen. Microbiol. 129:681-686, 1983; M. R. Volkert, L. J. Margossian, and A. J. Clark, J. Bacteriol. 160:702-705, 1984); we find that this suppression occurs at the earliest detectable phase of LexA cleavage and does not require protein synthesis. Our results support the idea that following UV irradiation, RecF enhances the activation of RecA into a form that promotes LexA cleavage (A. Thomas and R. G. Lloyd, J. Gen. Microbiol. 129:681-686, 1983; M. V. V. S. Madiraju, A. Templin, and A. J. Clark, Proc. Natl. Acad. Sci. USA 85:6592-6596, 1988). In contrast to the constitutive activation phenotype of the recA441 mutant, the recA441-mediated suppression of recF is not affected by adenine and nucleosides. We also find that wild-type RecA protein is somewhat activated by adenine in the absence of DNA damage.     

Mathematical theory of the possible role of intercellular fluid and of vascularization on physiological periodicities

In continuation of previous work (Rashevsky,Some Medical Aspects of Mathematical Biology, Springfield, Ill.: Charles C. Thomas, 1964, Chap. 23 and Appendix 14), the study of the effects of the physical parameters of the cells of endocrine glands on the onset of sustained periodical oscillations in the interaction between the anterior pituitary and the thyroid hormones is generalized to include the possible effect of the intercellular fluid and of the degree of vascularization. Some conclusions of the previous study remain valid although some modifications must be made. A decreased relative volume of the intercellular fluid and an increased vascularization favor the conditions for sustained oscillations. The permeability of the cells and the permeability of the capillaries appear explicitly in the expressions which show the conditions for sustained periodicities.     

ATP induces the release of a neutral serine proteinase and enhances the production of superoxide anion in membranes from phorbol ester-activated neutrophils

Plasma membranes isolated from human neutrophils after brief exposure to phorbol 12-myristate 13-acetate contain a large portion (30-40%) of the total cellular protein kinase C (Melloni, E., Pontremoli, S., Michetti, M., Sacco, O., Sparatore, B., Salamino, F., and Horecker, B. L. (1986) Biochem. Biophys. Res. Commun. 136, 228-234) and also retain almost 90% of their content of neutral serine proteinase (Pontremoli, S., Melloni, E., Michetti, M., Sacco, O., Sparatore, B., Salamino, F., Damiani, G., and Horecker, B. L. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 1685-1689). When ATP is added to the isolated membranes, a substantial amount (approximately 25%) of the intrinsic proteinase is released into the incubation medium. The addition of ATP in the presence of NADPH also caused a significant enhancement of the production of O2 radicals. These effects of ATP were not observed with membranes isolated from untreated neutrophils. The release of the serine proteinase is almost fully dependent on the addition of ATP and is correlated with the phosphorylation of membrane proteins. It is also markedly inhibited by the addition of retinal or trifluoperazine inhibitors of native protein kinase C. The results represent the first direct demonstration of a role for membrane-bound protein kinase C activity in the release of neutral proteinase and the production of O2 radicals, responses related to the cytotoxic effects of activated neutrophils.     

Extended and globular protein domains in cartilage proteoglycans.

Electron microscopy after rotary shadowing and negative staining of the large chondroitin sulphate proteoglycan from rat chondrosarcoma, bovine nasal cartilage and pig laryngeal cartilage demonstrated a unique multidomain structure for the protein core. A main characteristic is a pair of globular domains (diameter 6-8 nm), one of which forms the N-terminal hyaluronate-binding region. They are connected by a 25 nm-long rod-like domain of limited flexibility. This segment is continued by a 280 nm-long polypeptide strand containing most chondroitin sulphate chains (average length 40 nm) in a brush-like array and is terminated by a small C-terminal globular domain. The core protein showed a variable extent of degradation, including the loss of the C-terminal globular domain and sections of variable length of the chondroitin sulphate-bearing strand. The high abundance (30-50%) of the C-terminal domain in some extracted proteoglycan preparations indicated that this structure is present in the cartilage matrix rather than being a precursor-specific segment. It may contain the hepatolectin-like segment deduced from cDNA sequences corresponding to the 3''-end of protein core mRNA [Doege, Fernandez, Hassell, Sasaki & Yamada (1986) J. Biol. Chem. 261, 8108-8111; Sai, Tanaka, Kosher & Tanzer (1986) Proc. Natl. Acad. Sci. 83, 5081-5085; Oldberg, Antonsson & Heinegård (1987) Biochem. J. 243, 255-259].     

Bovine adrenocortical cells exhibit high affinity transforming growth factor-beta receptors which are regulated by adrenocorticotropin

Transforming growth factor beta (TGF-beta) at picomolar concentrations has been previously shown to induce striking alterations of bovine adrenocortical cell differentiated functions, without detectable effect on growth activity (Feige, J.J., Cochet, C., and Chambaz, E. M. (1986) Biochem. Biophys. Res. Commun. 139, 693-700; Hotta, M., and Baird, A. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 7795-7799). Adrenocortical cells in culture could bind 125I-labeled TGF-beta through at least two different binding systems. The highest affinity TGF-beta binding exhibited a Kd value of 5.7 X 10(-10) M and a calculated capacity of about 100,000 sites/cell, while the low affinity system yielded values of 4.3 X 10(-8) M and 2 X 10(6) sites/cell, respectively. The 125I-labeled TGF-beta bound to adrenocortical cells could be cross-linked using disuccinimidyl suberate and subsequent electrophoretic analysis revealed that TGF-beta was associated with two major cell components of about 280 kDa and 70-75 kDa, respectively, the latter one being resolved as a labeled doublet. Thus bovine adrenocortical cells exhibit a TGF-beta receptor similar to that defined by Massagué and co-workers (Cheifetz, S., Like, B., and Massagué, J. (1986) J. Biol. Chem. 261,9972-9978) in other cell types. Various growth factors, including fibroblast growth factor, as well as established hormonal activators of adrenocortical cell differentiated functions, such as angiotensin II and adrenocorticotropin, were examined as to their effect on TGF-beta receptor activity. A striking increase in the number of high affinity TGF-beta receptors was selectively elicited by ACTH in the nanomolar concentration range. This effect was time- and dose-dependent and was mimicked by cell treatment with dibutyryl cyclic AMP or forskolin. However, the ACTH-induced increase in receptor number was not impaired when protein synthesis was blocked. It is concluded that bovine adrenocortical cells are typical target cells for TGF-beta. This endocrine system represents a model in which, for the first time, the level of TGF-beta receptor is shown to be under hormonal regulation through a cyclic AMP-dependent pathway.     

The Cu(II)-repressible plastidic cytochrome c. Cloning and sequence of a complementary DNA for the pre-apoprotein

We have cloned a complementary DNA for pre-apocytochrome c-552 from Chlamydomonas reinhardtii. The deduced sequence of the mature protein shows high homology to those of cytochromes c-553 from cyanobacteria. Its homology to mitochondrial cytochrome c or bacterial photosynthetic cytochrome c2 is lower and appears to be concentrated in sequences around amino acids involved in the interaction with heme. With respect to primary sequence, the "transit sequence" for cytochrome c-552 appears to show no homology to other transit sequences for nuclear encoded chloroplast proteins. However, based on analogy to transit sequences for other proteins (Daldal, F., Cheng, S., Applebaum, J., Davidson, E., and Prince, R. C. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 2012-2016; Goldschmidt-Clermont, M., and Rahire, M. (1986) J. Mol. Biol. 191, 421-432; Smeekens, S., de Groot, M., van Binsbergen, J., and Weisbeek, P. (1986) Cell 46, 365-375) the transit sequence of cytochrome c-552 can be divided into envelope-traversing and thylakoid-traversing domains. Cytochrome c-552 appears to encoded by a single nuclear gene in C. reinhardtii. The gene is expressed exclusively in Cu(II)-deficient cells.