Expression of a bovine κ-CN cDNA in the mammary gland of transgenic mice utilizing a genomic milk protein gene as an expression cassette

Transgenic mice were produced by microinjection of a DNA construct composed of the bovine -casein (-CN) cDNA under the control of the goat -CN 5 promoter elements and 3 flanking regions into pronuclear-stage embryos. The gene construct targeted the expression of bovine -CN RNA to the mammary gland and secretion of bovine -CN in the milk. In the three lines studied (BC-7, BC-31 and BC-67) the transgene was stably integrated and propagated as a Mendelian locus. Expression of the bovine protein in lactating mice from the three transgenic lines was demonstrated by northern and western blots. In ten different tissues analysed by northern blotting, expression was confined to the mammary gland of lactating transgenic mice from line BC-7, with low-level expression also observed in the salivary gland of lines BC-31 and BC-67. Transgene expression in the mammary gland paralleled normal casein gene expression during lactation and was not observed in virgin females. The level of bovine -CN mRNA expression on day 10 of lactation in hemizygous transgenic females in relation to endogenous mRNA of whey acid protein (WAP) gene expression was 14%, 69% and 127% in lines BC-7, BC-31 and BC-67, respectively. No association between transgene copy number and expression was observed. The bovine -CN concentration in milk on day 10 of lactation ranged from 0.94 to 3.85 mg of protein per ml of milk. The bovine -CN expressed in mouse milk had the same molecular mass and immunoactivity with polyclonal antibodies as did -CN from bovine milk. A high degree of variation in the production of bovine -CN within each of the transgenic lines was observed.     

Monocyte-derived dendritic cells that capture dead tumor cells secrete IL-12 and TNF-α through IL-12/TNF-α/NF-κB autocrine loop

This study focused on the question of how monocyte-derived dendritic cells (Mo-DCs) that capture dead tumor cells (Mo-DCs-Tum) secrete interleukin 12 (IL-12) and tumor necrosis factor (TNF-). Mo-DCs-Tum showed higher secretions of IL-12 and TNF- than were shown by Mo-DCs. Enhanced nuclear factor-kappa B (NF-B) activation was also induced in Mo-DCs-Tum within 6 h. The NF-B inhibitor, pyrrolidine dithiocarbamate (PDTC), suppressed both IL-12 and TNF- secretions from Mo-DCs-Tum. Administration of recombinant TNF- or IL-12 enhanced IL-12 or TNF- secretion respectively in Mo-DCs-Tum. Addition of anti-TNF- or anti-IL-12 neutralizing antibody decreased NF-B activation and IL-12 or TNF- secretion in Mo-DCs-Tum. These results suggest that TNF- or IL-12 secretion induces NF-B activation, and it stimulates further TNF- and IL-12 secretions, i.e., an IL-12/TNF-/NF-B autocrine loop, in Mo-DCs-Tum. Thus, Mo-DCs-Tum secrete a large amount of IL-12 and TNF- through accelerated NF-B activation induced by the IL-12/TNF-/NF-B autocrine loop.     

Caseins of various origins and biologically active casein peptides and oligosaccharides: Structural and physiological aspects

Summary The first part of the present review is focused on structural aspects concerning the so far studied casein fractions of various origins: they are compared to the four classical major bovine caseins (_sl-, _s2- - and ). The calcium-sensitive casein fractions are always phosphorylated whereas -caseins are glycosylated. The study of the casein genes showed that the calcium-sensitive caseins diverged from a common ancestral gene and during the evolution, intergenic and intragenic duplications occurred. The considerable conservation of the phosphorylation sites emphasizes the importance of phosphorylated residues for the function of caseins, i.e. the formation of micelles and the binding of Ca²⁺. In -caseins all the prosthetic sugar groups are linked by O-glycosidic linkages: their number varies from 0 to 5 in bovine -casein and up to 10 in human -casein. The structures of the known -casein carbohydate moieties are described. Finally the milk clotting process (interaction -casein/chymosin) is compared to the blood clotting process (interaction fibrinogen/thrombin): a large number of similarities could be noted between both clotting phenomena.The second part of the review is devoted to the study of short casein peptides endowed with various biological activities. Some of them behaved as immunomodulators or casomorphins or angiotensin I converting enzyme inhibitors; others demonstrated an effect on platelet functions. A strategic zone containing immunostimulating and opioid peptides could be located in cow and human -caseins. Furthermore bitter peptides, emulsifying peptides, calcium absorption enhancing peptides, chymosin-inhibiting peptides, have also been described and several further properties have been attributed to the -caseinoglycopeptide; two tetrasaccharides isolated from the latter possess blood group activities.In conclusion caseins, the main milk proteins, should not only be considered as a nutriment but as a possible source of biologically active components.If, in the future, some of the discussed active peptides cannot be characterized in vivo, they can all, nevertheless, be synthesized and used either as food additives or in pharmacology.     

Pyridoxal-5′-phosphate derivatives of substance P: Preparation,spasmogenic activity,and degradation by human plasma

Two fluorescent derivatives of substance P (SP) (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH₂) were prepared by chemical modification of the native peptide by pyridoxal-5-phosphate (pyridoxal-P). The formation of both pyridoxal-P-derivatives of SP is the result of one modification procedure. The determination of the amino acid composition showed that in one of the derivatives the -amino group of the Lys residue [-(P-pxy)-SP] and in the other the -amino group of the Lys residue and also the N-terminal amino group [,-di-(P-pxy)-SP] of SP had been substituted by pyridoxal-P. -(P-pxy)-SP and ,-di-(P-pxy)-SP have spasmogenic activity with ED₅₀ of 1.8×10^–9 and 4×10^–9 M, respectively, tested on isolated guinea pig ileum. The fluorescence of P-pxy residues permits detection of as little as 1 pmol/ml of -(P-pxy)-SP and 0.5 pmol/ml of ,-di-(P-pxy)-SP. Both analogues of SP obtained are degraded by human plasma more slowly than the native peptide.Abbreviations SP substance P - pyridoxal-P pyridoxal-5-phosphate - P-pxy phospho-pyridoxyl residue - -(P-pxy)-SP substance P modified by pyridoxal-P at the -amino group of the Lys residue - ,-di-(P-pxy)-SP substance P modified by pyridoxal-P at the -amino group of the Lys residue and the N-terminal amino group of SP - (P-pxy)-Lys Lys modified by pyridoxal-P at the -amino group     

Stimulation of proliferation and immunoglobulin production of human-human hybridoma by various types of caseins and their protease digests

We have studied the effect of such milk proteins as caseins, lactalbumin, and lactoglobulin, on proliferation and immunoglobulin production of human-human hybridoma HB4C5 cells. It was found that -, -, and -caseins stimulated both proliferation and IgM product ion of human-human hybridoma HB4C5 cells, while the activities of -lactalbumin and -lactoglobulin were negligible. To localize the active sites of these caseins, effect of protease treatments on the activities were examined. When caseins were digested with trypsin, casein digests stimulated proliferation of the hybridoma, but not their IgM production. When -casein was digested with chymosin and fractionated top--casein and glycomacropeptide, both fragments stimulated proliferation of the cells, but onlyp--casein fragment stimulated IgM production. These results indicate that -casein has at least two proliferation stimulating sites and an IgM production stimulating site in thep--casein region.     

Localization of κ-casein on thin sections of casein micelles by the gold method

Summary The ultrastructural location of -casein in bovine casein micelles was investigated by the protein A-gold method. Casein micelles, fixed in glutaraldehyde, were embedded at low temperature to enhance immunocytochemical marking of thin sections. -Casein was found distributed throughout the micelles of all sizes with a higher concentration in the smaller micelles. No peripheral location of -casein was observed, even in the larger micelles. These results do not agree with coat-core structures proposed for casein micelles. However they favor models where -casein is distributed uniformly throughout the micelles.     

Thiol modulation of TNFα and IL-1 induced MnSOD gene expression and activation of NF-κB

TNF and IL-1 each can activate NF-B and induce gene expression of manganese superoxide dismutase (MnSOD), a mitochondrial matrix enzyme which can provide critical protection against hyperoxic lung injury. The regulation of MnSOD gene expression is not well understood. Since redox status can modulate NF-B and potential B site(s) exist in the MnSOD promoter, the effect of thiols (including NAC, DTT and 2-ME) on TNF and IL-1 induced activation of NF-B and MnSOD gene expression was investigated. Activation of NF-kB and increased MnSOD expression were potentiated by thiol reducing agents. In contrast, thiol oxidizing or alkylating agents inhibited both NF-B activation and elevated MnSOD expression in response to TNF or IL-1. Since protease inhibitors TPCK and TLCK can inhibit NF-B activation, we also investigated the effect of these compounds on MnSOD expression and NF-B activation. TPCK and TLCK each inhibited MnSOD gene expression and NF-B activation. Since the MnSOD promoter also contains anAP-1 binding site, the effect of thiols and thiol modifying agents on AP-1 activation was investigated. Thiols had no consistent effect onAP-1 activation. Likewise, some of the thiol modifying compounds inhibited AP-1 activation by TNF or IL-1, whereas others did not. Since diverse agents had similar effects on activation of NF-B and MnSOD gene expression, we have demonstrated that activation of NF-B and MnSOD gene expression are closely associated and that reduced sulfhydryl groups are required for cytokine mediation of both processes.Abbreviations O₂ Superoxide radical - H₂O₂ Hydrogen peroxide - NAC N-acetyl L-cysteine - DTT Dithiothreitol - 2-ME 2-Mercaptoethanol - MnSOD Manganese superoxide dismutase - NF-B Nuclear factor kappa B - AP-1 Activator protein-1 - NBT Nitroblue tetrazolium - CAT Chloramphenicol acetyltransferase - TPCK N-tosyl-L-phenylalanine chloromethyl ketone - TLCK Na-p-tosyl-L-lysine chloromethyl ketone - TAME N--p-tosyl-L-arginine methyl ester - NEM N-ethyl maleimide - DEM Diethyl maleate - CDNB 1-chloro-2,4-dinitrobenzene - DTT_OX Oxidized dithiothreitol     

Phosphoinositide 3-kinase activity leads to silica-induced NF-κB activation through interacting with tyrosine-phosphorylated IκB-α and contributing to tyrosine phosphorylation of p65 NF-κB

The role of the subunits of phosphoinositide (PI) 3-kinase in NF-B activation in silica-stimulated RAW 264.7 cells was investigated. Results indicate that PI3-kinase activity was increased in response to silica. The p85 subunit of PI3-kinase interacted with tyrosine-phosphorylated IB- in silica-stimulated cells. PI3-kinase specific inhibitors, such as wortmannin and LY294003, substantially blocked both silica-induced PI3-kinase and NF-B activation. The inhibition of NF-B activation by PI3-kinase inhibitors was also observed in pervanadate-stimulated but not in LPS-stimulated cells. Furthermore, tyrosine phosphorylation of NF-B p65 was enhanced in cells stimulated with silica, pervanadate or LPS, and wortmannin substantially inhibited the phosphorylation event induced by the first two stimulants but not LPS. Antioxidants, such as superoxide dismutase (SOD), N-acetylcysteine (NAC) and pyrrolidine dithiocarbamate (PDTC), blocked silica-induced PI3-kinase activation, suggesting that reactive oxygen species may be important regulatory molecules in NF-B activation by mediating PI3-kinase activation. Our data suggest that p85 and p110 subunits of PI3-kinase play a role in NF-B activation through interaction with tyrosine-phosphorylated IB- and contributing to tyrosine phosphorylation of p65 NF-B.     

Polyamine depletion inhibits etoposide-induced NF-κB activation in transformed mouse fibroblasts

Summary. In a previous research, we have shown that adequate levels of polyamines are required in transformed mouse fibroblasts for the correlated activations of MAPK subtypes (ERK and JNK) and caspases induced by etoposide and leading to apoptosis. We report now that the treatment of fibroblasts with etoposide also elicited a progressive and sustained increase of NF-B activation. The DNA binding activity of p65 NF-B subunit was increased up to approximately 4-fold and was accompanied by enhancement of p65 phosphorylation. A two days pre-treatment of fibroblasts with -difluoromethylornithine (DFMO), which caused polyamine depletion, provoked a slight activating effect when given alone, but markedly inhibited the etoposide-induced increases in p65 DNA binding and phosphorylation. The NF-B inhibiting effect of DFMO was prevented by the addition of exogenous putrescine, which restored the intracellular content of polyamines. Selective inhibitors of the etoposide-stimulated MAPK subtypes also reduced NF-B activation. Moreover, pharmacological NF-B inhibition reduced the increase in caspase activity and cell death elicited by etoposide, suggesting that NF-B is involved in signaling to apoptosis. The results of the present study, together with our previous findings, suggest that polyamines play a permissive role in the pathways triggered by etoposide and leading to cell death of fibroblasts, by supporting the activation of MAPKs, NF-B and caspases.     

Induction of cyclooxygenase-2 expression in human tracheal smooth muscle cells by interleukin-1β: Involvement of p42/p44 and p38 mitogen-activated protein kinases and nuclear factor-κB

Interleukin-1 (IL-1) has been recognized as a potent stimulus for the synthesis of prostaglandin (PG), which has been implicated in inflammatory responses of the airways. However, the mechanisms underlying IL-1-induced cyclooxygenase (COX) expression and PGE₂ synthesis via activation of p42/p44 and p38 mitogen-activated protein kinases (MAPKs) in human tracheal smooth muscle cells (HTSMCs) are not completely understood. We found that IL-1 increased COX-2 expression and PGE₂ synthesis in time- and concentration-dependent manners. Both specific phosphatidylcholine-phospholipase C inhibitor (D609) and protein kinase C inhibitor (GF109203X) attenuated IL-1-induced responses in HTSMCs. IL-1-induced COX-2 expression and PGE₂ synthesis were also inhibited by an inhibitor of MEK1/2 (PD98059) and inhibitors of p38 MAPK (SB203580 and SB202190), respectively, suggesting the involvement of p42/p44 and p38 MAPKs in these responses. This hypothesis was further supported by the transient activation of p42/p44 and p38 MAPKs induced by IL-1. Furthermore, IL-1-induced activation of nuclear factor-B (NF-B) was inversely correlated with the degradation of IB- in HTSMCs. IL-1-induced COX-2 expression and PGE₂ synthesis were inhibited by the NF-B inhibitor pyrrolidinedithiocarbamate. These findings suggest that the expression of COX-2 is correlated with the release of PGE₂ from IL-1-challenged HTSMCs, which is mediated, at least in part, through p42/p44 and p38 MAPKs and NF-B signaling pathways in HTSMCs.     

Protocol-dependence of equivalent circuit parameters of toad urinary bladder

Summary Determinations of current-voltage relationships are widely employed in the characterization of epithelial sodium transport. In order to determine the protocol dependence of transport parameters in the toad urinary bladder, studies were carried out in the presence and absence of amiloride, an inhibitor of active sodium transport. With symmetric positive and negative perturbations of the transepithelial electrical potential difference (0±100 mV) for 30 sec, the amiloride-sensitive current-voltage (i ^a -) relationship was near linear over the range –75+100 mV, indicating constancy of the conductance ^a and the apparent electromotive force E _Na, lumped parameters of the standard electrical equivalent circuit model of the active transport system. With a reverse protocol (±1000 mV) or 15 min perturbations thei ^a - relationships were highly nonlinear. Nonlinearity reflected voltage dependence of parameters: perturbations that increased active transport decreased E _Na and increased ^a, as evaluated from 10 sec perturbations of ; slowing of active transport produced the converse changes. These effects are usefully analyzed in both quasi-steady states and true steady states by means of a detailed equivalent circuit incorporating the significant ionic currents across each plasma membrane. Precise understanding of the significance of ^a and E _Na will require characterization of the partial ionic conductances on perturbation of .     

Structural relatedness ofκ-casein and fibrinogenγ-chain

Summary -Caseins, involved in the milk clotting process, and human fibrinogen-chain, involved in the blood clotting process, show structural similarities. Several long-casein sections, together corresponding to 80% of the whole protein molecule, have their counterparts in the-chain of fibrinogen, in that 31-42% of the amino acid residues occupy identical positions. The section of-casein which contains the chymosin-sensitive bond has a counterpart not only in the but also in the B-chain of fibrinogen. Furthermore, the secondary structures of the-caseins and of the-chain predicted according to the method of Chou and Fasman present several common features.41th communication on caseins.     

Linked genetic markers of the rabbit κ light chain are not linked to the Tcr β chain genes

In order to investigate linkage, we used serum allotypes of the two rabbit C isotypes and restriction fragment length polymorphisms (RFLPs) of the genes for V , C , and T-cell receptor C . The inheritance of these genetic markers was studied through backcross and F₂ matings. Southern analysis and hybridization of genomic DNA with a C probe detected a 5 kb Pst I fragment linked to expression of the K2bas1 allotype and the presence of the 1b ^bas gene and a 6.6 kb Pst I fragment linked to the expression of the K1b9 allotype, the presence of the 2 ^bas2 gene and lack of expression of the K2bas1 allotype. A V probe detected a 1.3 kb Eco RI fragment linked to the presence of the 1b ^bas gene and expression of the K2bas1 allotype. In contrast, the 9 or 14 kb Eco RI RFLP (C ^a or C ^b) detected with a Tcr chain probe segregated independently from C allotypes and RFLPs. It has previously been found that C and C are also unlinked in man, whereas in the mouse they are linked at a distance of 8 centimorgans.     

On age morphological changes of males of Chydoridae (Cladocera)

Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.     

Linkage of the β-Like ω-Globin Gene to α-Like Globin Genes in an Australian Marsupial Supports the Chromosome Duplication Model for Separation of Globin Gene Clusters

The structure, function, and evolutionary history of globin genes have been the subject of extensive investigation over a period of more than 40 years, yet new globin genes with highly specialized functions are still being discovered and much remains uncertain about their evolutionary history. Here we investigate the molecular evolution of the -globin gene family in a marsupial species, the tammar wallaby, Macropus eugenii. We report the complete DNA sequences of two -like globin genes and show by phylogenetic analyses that one of these genes is orthologous to embryonically expressed -globin genes of marsupials and eutherians and the other is orthologous to adult expressed -globin genes of marsupials and eutherians. We show that the tammar wallaby contains a third functional -like globin gene, -globin, which forms part of the -globin gene cluster. The position of -globin on the 3 side of the -globin cluster and its ancient phylogenetic history fit the criteria, originally proposed by Jeffreys et al. (1980), of a fossil -globin gene and suggest that an ancient chromosome or genome duplication preceded the evolution of unlinked clusters of - and -globin genes in mammals and avians. In eutherian mammals, such as humans and mice, -globin has been silenced or translocated away from the -globin locus, while in marsupials -globin is coordinately expressed with the adult -globin gene just prior to birth to produce a functional hemoglobin (_{2 2}).     

Protease inhibitor localization in control and streptozotocin-diabetic skeletal muscles

Summary ₁-Antitrypsin and ₁-inhibitor-3 were localized for the first time inside skeletal muscle cells. Their content, especially that of ₁-inhibitor-3, was greatly reduced following streptozotocin-induced diabetes. ₁-Antitrypsin and ₁-inhibitor-3 were also observed in the vascular components and interstitial space surrounding both control and diabetic soleus muscles as revealed by immunofluorescence. In diabetic muscles, the non-myofibre locale of ₁-inhibitor-3 was reduced, and to a lesser extent, ₁-antitrypsin. Both myofibre and extracellular patterns were reversed to control levels by insulin replacement.     

Effect of organic and inorganic fertigation on yields, δ15N values, and δ13C values of tomato (Lycopersicon esculentum Mill. cv. Saturn)

We examined the effects of fertilizer application, especially the effects of fertigation and types of fertilizer (inorganic and organic) on yields and ¹⁵N and ¹³C values of tomato (Lycopersicon esculentum Mill. cv. Saturn). Fertigation is a method in which an appropriate diluted liquid fertilizer is applied to the plants each time they are drip-irrigated. We developed a method of organic fertigation using corn steep liquor (CSL) as the liquid fertilizer, because it is an industrial byproduct of cornstarch manufacture and can be used very effectively. We compared fruit yield, mineral content, ¹⁵N value, and ¹³C value of tomatoes grown under three different fertilizer treatments, basal dressing: basal dressing with granular chemical fertilizer; inorganic fertigation: fertigation with liquid chemical fertilizer; and organic fertigation: fertigaion with CSL. Mineral contents of tomatoes grown with basal dressing were generally lower than those grown under either fertigation treatment. These results indicated that yields and mineral contents were influenced more by the method of fertilizer application than by whether the fertilizers were inorganic or organic. There were, however, significant differences in the ¹⁵N values of tomato fruits grown under different types of fertilizer applications, especially between inorganic and organic fertilizers. The ¹⁵N value of the chemical fertilizer used for basal dressing was 0.81 ± 0.45{}, that of the chemical fertilizer for fertigation was 0.00 ± 0.04{}, and that of CSL was 8.50 ± 0.71{}. The ¹⁵N values of the soils reflected the ¹⁵N values of the fertilizers. Moreover, the ¹⁵N values of the fruits corresponded to the ¹⁵N values of the applied fertilizers. The ¹⁵N values were 3.18 ± 1.34{} in the fruits grown with a basal dressing of chemical fertilizer, 0.30 ± 0.61 in those grown under inorganic fertigation, and 7.09 ± 0.68 in those grown under organic fertigation. On the other hand, although the ¹³C values in the soil also reflected the ¹³C values of the applied fertilizers, there was no significant difference in the ¹³C values of fruits among the different treatments. In conclusion, because the ¹⁵N values of fertilizers correlated well with those of the fruits, it may be possible to use ¹⁵N values as an indicator of organic products.     

Interactions between NFκB and Its Inhibitor iκB: Biophysical Characterization of a NFκB/iκB-α Complex

The N-terminal domain (1–318 amino acids) of mouse NFB (p65) has been purified to homogeneity from the soluble fraction of Escherichia coli cells expressing this protein. Its complex with a full-length iB- (MAD3, 1–317 amino acids) molecule was generated by binding the E. coli-derived iB- to the purified NFB and purifying the complex by sequential chromatography. The stoichiometry of NFB to iB in the complex was determined to be 2 to 1 by light scattering and SDS–polyacrylamide gel electrophoresis. The secondary structure of the NFB (p65) determined by Fourier-transform infrared (FTIR) spectroscopy is in good agreement with that of the p50 in the crystal structure of the p50/DNA complex, indicating that no significant structural change in NFB occurs upon binding of DNA. The FTIR spectrum of the NFB/iB complex indicates that its secondary structure is composed of 17% -helix, 39% -strand, 18% irregular structures, and 26% -turns and loops. By comparing these data to the FTIR data for NFB alone, it is concluded that the iB (MAD3) in the complex contains 35% -helix, 27% -strand, 22% irregular structures, and 16% -turns and loops. Circular dichroism (CD) analysis of a shorter form of iB (pp40) indicates that it contains at least 20% -helix and that the iB subunit accounts for nearly all of the -helix present in the NFB/iB complex, consistent with the FTIR results. The stabilities of NFB, iB, and their complex against heat-induced denaturation were investigated by following changes in CD signal. The results indicate that the thermal stability of iB is enhanced upon the formation of the NFB/iB complex.     

Partial mispairing and crossing-over between β0 and δ genes as the origin of the δ β0 thalassemia gene

Summary Two double heterozygous ⁰/⁰ thalassemic sibs of Mexican descent were studied. The father had a ⁰/⁰ genotype, while the mother, one sib and several maternal relatives were ⁰/⁰ heterozygotes. Parental consanguinity and an apparently low frequency of thalassemia among Mexicans suggested a possible common origin of both ⁰ and ⁰ genes. A hypothesis to explain such a possibility is proposed on the basis of a partial mispairing between ⁰ and genes followed by a crossing-over which would results in a ⁰ recombinant gene. This hypothesis could also be extended to explain the 22 gluala, 22 alaglu and 116 arghis Hb variants as recombinants from double crossing-over between and mispaired genes for which the name interstitial-Lepore is proposed.     

Genetic polymorphism at the κ chain locus in mice: Comparisons of restriction enzyme hybridization fragments of variable and constant region genes

Variable (V) and constant (C) region genes of the mouse kappa light chain have been compared in inbred strains and in geographically isolated or genetically separated populations of mice by Southern blot analysis of endonuclease-restricted germline DNA. In most cases, the C gene is found on a single restriction fragment while the V genes of the V19 and V21 groups are each found on several (6–18) fragments. The restriction fragment (RF) patterns of V19 and V21 groups are both polymorphic when compared among inbred mouse strains. Southern blot patterns of V21 and V19 of inbred strains are also found among some geographically isolated populations of mice, suggesting that inbred strains acquired kappa loci from different subspecies. Some populations of geographical isolates show V21, V19, and C contexts similar to inbred mice while more distantly related species within the genus Mus and laboratory rats show no apparent similarity in context to inbred strains. Variable region genes determining the RF patterns of V19 and V21 appear to be linked to each other and to the C and Lyt-3 loci.