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J C Regier

Publications and source records attributed to J C Regier.

At least 37 records · Page 2Linked to original sources
PubMed1987

Evolutionary changes in the developmental expression of silkmoth chorion genes and their morphological consequences.

Discrete changes in silkmoth choriogenesis have occurred during evolution, as exemplified in the present report in Antheraea polyphemus and Hyalophora cecropia. At the level of morphology, the chorion of A. polyphemus has surface structures, called aeropyle crowns, that are absent from H. cecropia. Aeropyle crowns form during the very late period of choriogenesis and consist of two substructures--lamellae and filler. Filler is present in H. cecropia in greatly reduced amounts. At the level of protein synthesis, overall similarities in the two species are maintained until the very late period of choriogenesis, when synthesis of aeropyle crown components is maximal. In H. cecropia, very late period-specific proteins are reduced in number and abundance. Several of these minor proteins are candidates for E1 and E2, the components of filler. E1 and E2 RNAs are about 35 times more abundant in A. polyphemus, despite very similar gene copy numbers and times of expression in the two species. These results support the hypothesis that evolutionary changes in chorion morphology have resulted from regulatory changes in the expression of chorion genes, either at the level of transcription or mRNA decay. The hypothesis that evolutionary changes in chorion morphology are based on terminal addition onto a preexisting developmental program is discussed.

Animals↗
PubMed1986

Evolution and higher-order structure of architectural proteins in silkmoth chorion.

Genomic and cDNA clones have been sequenced that encode the E2 silkmoth chorion protein. E2 assembles with E1 [Regier, J.C. and Pacholski, P. (1985) Proc. Natl. Acad. Sci. USA, 82, 6035-6039] to form the 'filler' that helps mold prominent chorion surface structures called aeropyle crowns. E2 has two distinct domains. The amino terminal domain consists of four alternating stretches of hydrophobic and hydrophilic residues, the first three of which are homologous in sequence to about half of the E1 protein. Comparison of predicted secondary structures provides further support for the localized homology of E2 and E1. The carboxy terminal domain of E2 is much longer, is hydrophilic and consists entirely of multiple tandem copies of a single, variant hexapeptide repeat sequence that is absent from E1. Numbers of hexapeptide repeat sequences differed dramatically in two animals. The types of events required for such variation are discussed. Finally, we have elaborated our earlier model for how E proteins may assemble in vivo to form filler.

Amino Acid Sequence↗
PubMed1986

Patterns of region-specific chorion gene expression in the silkmoth and identification of shared 5' flanking genomic elements.

Time-dependent and cell-specific changes in concentrations of total RNA, of poly A+ RNA, and of specific mRNAs have been measured throughout silkmoth choriogenesis. Levels of total RNA and of poly A+ RNA are maintained throughout much of choriogenesis, but decrease at least fourfold during the very late period, in parallel with a decrease in overall protein synthesis. Very late period changes in total RNA and in poly A+ RNA are less pronounced in the aeropyle crown region, where a subset of chorion proteins is preferentially synthesized, than in the flat region. Maximal accumulation of the E1 and E2 chorion mRNAs occurs preferentially in the aeropyle crown region during the very late period. Uridine pulse-labeling studies suggest that E1 and E2 transcription is similarly aeropyle crown region-specific and immediately precedes the time of maximal E1 and E2 RNA accumulation and protein synthesis. Sequences from the 5' flanking regions of E1 and E2 genes have been compared. Several oligonucleotide sequences are present in both genes, and some are duplicated. These are potential cis-acting, regulatory elements.

Animals↗
PubMed1986

Organization of regionally expressed silkmoth chorion genes.

We described the organization of two silkmoth chorion genes, called E1 and E2, whose expression is largely restricted in time to the very late period of choriogenesis and in space to one of two major subpopulations of follicle cells. Using E1 and E2 clone cDNAs as probes, we showed that gene copy numbers per haploid genome remain constant throughout silkmoth development despite major changes in total DNA content per nucleus. Furthermore, gene copy numbers are the same in both cellular regions of the choriogenic follicle despite differences in nuclear size and levels of E gene expression. Southern analysis indicated between two and four copies each for E1 and E2 genes. Analysis of chromosomal clones showed that single copies of E1 and E2 are separated by about 7.5 kilobases and are transcribed from the same DNA strand. Two distinct pairs of cloned E1 and E2 genes were characterized. No other chorion genes were in their immediate vicinity.

Animals↗
PubMed1985

Nucleotide sequence of an unusual regionally expressed silkmoth chorion RNA: predicted primary and secondary structures of an architectural protein.

We have sequenced DNA clones corresponding to the entire coding and 5' untranslated regions and almost all of the 3' untranslated region of a silkmoth chorion RNA which is expressed largely in a subpopulation of follicular epithelial cells (aeropyle crown region). This RNA encodes the E1 protein, one of two components of the prominent "filler" that helps mold the shape of aeropyle crowns. The conceptually translated E1 sequence reveals an alternation in hydrophobic and hydrophilic stretches of amino acids that correlates with certain predictions about its secondary structure. E1 is unusual in revealing no sequence homology with other known chorion sequences and in having an unusually long 3' untranslated region. Sequence analysis of the 5' end of the E1 gene has identified an intron near the end of the signal peptide-encoding region, a feature shared with other chorion genes.

Amino Acid Sequence↗
PubMed1984

Molecular cloning of region-specific chorion-encoding RNA sequences.

We have constructed a cDNA clone library from poly(A)+ RNA of very-late-period choriogenic silkmoth follicles. Clone DNAs that hybridize preferentially to RNA from the aeropyle crown region of the follicle (versus the flat region) were selected, and all could be placed in one of two homology groups. The two groups represent sequences encoding the very-late-period chorion proteins E1 and E2; this was established by hybrid-selected translation coupled with specific antibody precipitation. Regionalized synthesis of chorion proteins is restricted to the very late period, and its control can now be studied at the nucleic acid level.

Age Factors↗
PubMed1983

The B multigene family of chorion proteins in saturniid silkmoths.

The main features of the B family of chorion proteins in saturniid moths were examined by partial sequencing of representative B proteins, seven from Antheraea polyphemus and two from A. pernyi. Comparisons were made to sequences derived from seven recombinant DNA clones representing three types of B family proteins of A. polyphemus. The central regions of the sequences are conservative, both within and between moth species, and differ largely by a few amino acid replacements, rather than deletions or insertions. By contrast, the amino-terminal third varies more substantially, in a manner which defines two protein subfamilies: within each subfamily sequences are similar, but the subfamilies differ by at least two multiresidue deletions as well as by amino acid replacements. These properties are analogous to features of the A family of chorion proteins.

Amino Acid Sequence↗
PubMed1983

Silkmoth chorion multigene families constitute a superfamily: comparison of C and B family sequences.

We have characterized a new family of silkmoth chorion genes, called C, which is distinct from previously characterized A and B families. The amino acid compositions of 18 purified C proteins have been determined. Three subgroups are recognized on the basis of compositional similarities and may correspond to distinct gene families or subfamilies. The sequences of two overlapping cDNA clones have been determined in their entirety and shown to correspond to a C-specific sequence. Obvious homology is observed between the middle portions of the C sequence and previously characterized B sequences. By contrast, the arms of the C sequence share no significant similarities either with each other or with the corresponding arms of B sequences. Thus, the same tripartite structure originally observed in A and B family sequences is also present in the C family and may have functional significance. Secondary structure prediction of the C sequence is presented and supports this conclusion. The observed homology between C and B family sequences clearly establishes that silkmoth chorion multigene families constitute a superfamily.

Amino Acid Sequence↗
PubMed1981

In vivo kinetics of pyrrolidonecarboxylic acid formation in selected silkmoth chorion proteins.

The protein products from one of the two major silkmoth chorion multigene families contain blocked NH2 termini. The blocked residue has been identified as pyrrolidonecarboxylic acid. Its formation occurs post-translationally, by modification of NH2-terminal glutamine, after removal of a 20-residue-long "signal peptide." Pyrrolidonecarboxylic acid formation begins within minutes after polypeptide chain termination and is largely, although not entirely, complete by 60 min. Pyrrolidonecarboxylic acid thus appears to be formed both within the cell and in the extracellular chorion. Another class of minor chorion proteins also appears to contain pyrrolidonecarboxylic acid.

Amino Acid Sequence↗
PubMed1980

Selection and sequence analysis of a cDNA clone encoding a known chorion protein of the A family.

Using as criteria the size, abundance and developmental specificity of hybridizing mRNA sequences, we have selected from our chorion cDNA library a clone corresponding to a specific chorion protein, A4--cl. Comparison between the clone sequence and the largely known sequence of A4--cl validates the use of the cDNA library for sequence analysis of the chorion multigene families. The two major chorion protein families, A and B, share certain structural similarities.

Amino Acid Sequence↗
PubMed1978

Silkmoth chorion proteins. Their diversity, amino acid composition, and the NH-terminal sequence of one component.

Silkmoth eggshell (chorion) proteins have been characterized by electrophoresis on sodium dodecyl sulfate and isoelectric focusing polyacrylamide gels; up to 33 and 41 components, respectively, were detected from a single chorion. Some of these components are polymorphic, being absent from chorions of certain animals. A system of nomenclature for all chorion proteins is presented, based on their separation on sodium dodecyl sulfate and isoelectric focusing gels. The chorion is enriched in glycine, alanine, cysteine, and tyrosine and poor in methionine and histidine. The proteins were fractionated into four partially overlapping groups; all four are enriched in the above amino acids, although significant differences exist. Further fractionation by isoelectric focusing of one of the above groups, s/s, yielded seven components, two of which are homogeneous both on sodium dodecyl sulfate and isoelectric focusing gels. The amino acid compositions, molecular weights, and solubility properties of the components share certain features which distinguish s/s as a group from the other three groups. The sequence of the first 67 NH2-terminal residues of a homogeneous protein purified from s/s has been determined. The protein contains a cysteine-rich tail (3 cysteines in the first 18 residues) followed by a 49-residue segment which contains only a single cysteine residue. This latter segment also contains two different tetrapeptide sequences which are each repeated, one twice and the other four times.

Amino Acid Sequence↗
PubMed1978

Silkmoth chorion proteins: sequence analysis of the products of a multigene family.

Five polypeptide components have been isolated from the eggshell (chorions) of a silkmoth. Two are homogeneous on sodium dodecyl sulfate and isoelectric focusing gels, and three contain predominantly two proteins each. Amino acid analyses show that all five components are similar to each other. These proteins have been sequenced from the amino terminus. Homogeneous components yielded single sequences; heterogeneous components yielded two residues at some positions, consistent with their containing two major electrophoretic components. Striking similarities are apparent among all these sequences. These similarities can be increased dramatically by separating each of the three protein mixtures into two sequences and introducing a small number of gaps or insertions. This is due in part to bringing into register a portion that contains short repeating subunits found in all sequences. All proteins are also characterized by a region of high cysteine content near the amino terminus followed by a longer low-cysteine region. The data suggest that these proteins share a common evolutionary origin and are encoded by a multigene family.

Amino Acid Sequence↗