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Results for “third generation sequencing”

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PubMed1992

Differential splicing in the extracellular region of fibroblast growth factor receptor 1 generates receptor variants with different ligand-binding specificities.

We have cloned a genomic region of the murine fibroblast growth factor (FGF) receptor 1 (FGFR1) gene that includes three alternative exons for the third immunoglobulinlike domain in the extracellular region of the receptor. The mRNA of one of these splice variants encodes a secreted receptor that lacks transmembrane and cytoplasmic sequences as well as a portion of the third immunoglobulinlike domain. Highest levels of mRNA encoding this variant were found in brain, skeletal muscle, and skin. We expressed this form of FGFR1 in CHO cells and showed that the recombinant secreted protein binds acidic FGF. We also discovered a novel alternative exon in the third immunoglobulinlike domain that encodes part of a transmembrane FGFR1 mRNA. This exon is highly homologous to the corresponding region of the keratinocyte growth factor receptor. Transcripts including this exon were present at highest levels in the skin. We cloned an FGFR1 cDNA which includes this exon and expressed this receptor variant in L6 rat skeletal muscle myoblasts. The new receptor variant had a 50-fold-lower affinity for basic FGF than does the published FGFR1 variant, whereas both forms of receptor bound acidic FGF with high affinity. These results show that the third immunoglobulinlike domain plays an important role in determining the binding specificities for different FGFs. Our data provide the first evidence that differential splicing in the extracellular region of a receptor gene generates receptor variants with different ligand-binding specificities.

Amino Acid Sequence↗

PubMed1997

Free radical induced polymerization of synthetic peptides into polymeric immunogens.

Free radical induced polymerization of vinyl monomers such as the acryloyl peptides described here is a facile and rapid reaction used routinely, for example, in the polymerization of acrylamide and bisacrylamide for the assembly of polyacrylamide gels. The technology allows the incorporation of many of the same or different peptide determinants into a single polymer chain. In this study large polymers containing multiple copies of peptides representing T- and B-cell determinants of influenza haemagglutinin were constructed. The determinants retained antigenicity after the polymerization procedure and the polymers were highly immunogenic; the levels of antibody obtained after a single dose of polymeric immunogen were at least as great as those achieved only after repeated doses of the equivalent monomeric peptide. The technology has a wide range of potential applications, not the least significant of which is the construction of designer immunogens for third generation vaccine candidates.

Amino Acid Sequence↗

PubMed1991

P300 generation by novel somatosensory stimuli.

Event-related potentials (ERPs) to task-relevant target and task-irrelevant novel stimuli were recorded in a somatosensory discrimination task. Subjects pressed a button to mechanical taps of the fifth finger (targets, P = 0.12), randomly interposed in sequences of taps to the second finger (standards, P = 0.76). Two types of infrequent novel stimuli were delivered; one was a mechanical tap to the third or fourth finger (tactile novels, P = 0.06), another was an electric shock at the wrist (shock novels, P = 0.06). Correctly detected targets generated a parietal maximal P300 (P3b, latency 335 msec). Shock novels generated a central maximal P300 with a shorter peak latency (298 msec) than the P3b. Tactile novels generated a P300 with a scalp distribution comparable to the shock novels. Unlike the P3b, P300 amplitude to both the shock and tactile novel stimuli habituated by 20-30% across the first several stimulus presentations. These results indicate that, similar to the auditory and visual modality, task-irrelevant novel somatosensory stimuli generate a novelty P300 ERP. Differences in scalp distribution, latency and habituation characteristics suggest that the novelty P300 may have contributions from intracranial generators independent from target P300 sources.

Adolescent↗

PubMed1981

Identification of D segments of immunoglobulin heavy-chain genes and their rearrangement in T lymphocytes.

The finding that the diversity (D) and joining (JH) but not the variable (VH) DNA segments of mouse immunoglobulin heavy-chain genes are joined in the DNA of some cloned cytolytic T cells, led to identification and sequencing of three different D DNA segments. Two segments identified on the embryo DNA carry on both the 5' and 3' sides two sets of characteristic sequences separated by a 12-base pair spacer, which have been implicated as recognition signals for a recombinase. The third segment, identified in a form joined with a JHDNA segment in a T cell, carries the recognition signal on the 5' side. These results support the 12/23-base pair model for somatic generation of immunoglobulin V genes, and rule out the possibility that the cytolytic T cells use assembled VH, D and JH sequences to encode their antigen receptors.

Animals↗

PubMed1994

Alternative splicing generates two distinct transcripts for the Drosophila melanogaster fibroblast growth factor receptor homolog.

We screened Drosophila melanogaster genomic and cDNA libraries by low-stringency hybridization with a probe representing the protein tyrosine kinase (TyK) domain encoded by a human alpha-platelet-derived growth factor receptor-encoding cDNA. The complete sequences of the open reading frames and 3'-untranslated regions (UTR) of some cross-hybridizing clones were identical to the recently published sequence of DFR1, encoding the novel D. melanogaster fibroblast growth factor receptor homology. However, two species of DFR1 cDNAs were isolated that differed with respect to their 5'-UTR. Analysis of the genomic organization revealed that DFR1 is composed of three exons. The entire coding region is contained within the third exon. S1 mapping and RNase-protection assays demonstrated that two distinct DFR1 transcripts possessing either the first or the second exon in combination with the third exon are generated by alternative splicing. This suggests that the transcriptional, as well as posttranscriptional, regulation of fibroblast growth factor receptor (FGFR)-encoding genes during D. melanogaster development is likely to be complex.

Alternative Splicing↗

PubMed1988

Ancient origin of lactalbumin from lysozyme: analysis of DNA and amino acid sequences.

Parsimony trees relating DNA sequences coding for lysozymes c and alpha-lactalbumins suggest that the gene duplication that allowed lactalbumin to evolve from lysozyme preceded the divergence of mammals and birds. Comparisons of the amino acid sequences of additional lysozymes and lactalbumins are consistent with this view. When all base positions are considered, the probability that the duplication leading to the lactalbumin gene occurred after the start of mammalian evolution is estimated to be 0.05-0.10. Elimination of the phylogenetic noise generated by fast evolution and compositional bias at third positions of codons reduced this probability to 0.002-0.03. Thus the gene duplication may have long preceded the acquisition of lactalbumin function.

Animals↗

PubMed1990

Alternative splicing of the human alpha 2(VI) collagen gene generates multiple mRNA transcripts which predict three protein variants with distinct carboxyl termini.

We recently reported the isolation and sequencing of two classes of human alpha 2(VI) collagen cDNA clones which share common sequences for the first two-thirds of the molecule but contain a different sequence of either 607 or 887 base pairs at their 3' ends (Chu, M.-L., Pan, T.-C., Conway, D., Kuo, H.-J., Glanville, R. W., Timpl, R., Mann, K., and Deutzmann, R. (1989) EMBO J. 8, 1939-1946). In the present study, we report the sequence of another cDNA clone, which is identical to one class of the previously isolated cDNAs except for a 293-base pair insertion between the common and variable regions. Together, the different classes of cDNAs, referred to as the alpha 2C2, alpha 2C2a, and alpha 2C2a' predict three variant alpha 2 chains of type VI collagen with carboxyl globular domains of 429, 328, and 238 amino acid residues, respectively. In order to explore the mechanisms by which the variations are generated, we isolated and characterized the 3' end of the human alpha 2(VI) collagen gene. The carboxyl globular domain was found to be encoded by six exons which appear to delineate its structural subdomains. The exon/intron arrangement clearly demonstrated that the cDNA variants arose from alternative splicing events by mutually exclusive utilization of the last two exons in conjunction with the selective usage of an internal splice acceptor site in the penultimate exon. The presence of the corresponding mature mRNA transcripts (3.2-3.5 kilobase pairs (kb] in human fibroblasts was shown by Northern blot hybridization, S1 nuclease protection assay, and the polymerase chain reaction. The results indicated that the alpha 2C2 mRNA is the major species, whereas the alpha 2C2a and alpha 2C2a' are the minor forms. Northern blot hybridization also revealed an alpha 2(VI) collagen mRNA of 6.0 kb. This mRNA retained a 2.3-kb intron located between the two alternatively spliced exons and predicted a translational product that is the same as the alpha 2C2a variant.

Amino Acid Sequence↗

PubMed1993

Identification of a natural killer enhancing factor (NKEF) from human erythroid cells.

We have previously shown that RBC significantly augment NK cell-mediated cytotoxicity when added at the initiation of cytotoxicity assays. We now report that RBC cytosol contains a soluble factor that mediates a similar enhancement of NK activity when the factor is precoated on a plastic surface. We have purified this NKEF by ammonium sulfate precipitation, ion exchange chromatography, and gel filtration HPLC. While gel filtration HPLC shows that NKEF has an apparent molecular mass of between 300 and 400 kDa, SDS-PAGE analysis indicates an apparent molecular weight of 48 and 24 kDa under nonreducing and reducing conditions, respectively. Immune serum obtained from a rabbit immunized with purified NKEF blocks NKEF augmentation of NK activity. In contrast, preimmune serum fails to inhibit NKEF activity. Anti-NKEF antibody reacts with the cytosol of NK-sensitive erythroleukemic target cell K562. Western blot analysis indicates that this antibody recognizes a 24-kDa protein both in RBC and in K562. We have generated tryptic peptides from NKEF and obtained partial amino acid sequences from three of the peptides. Two of the sequences show no significant homology with any known sequences. The third sequence shows partial identity with a deduced sequence from a murine erythroleukemia-related gene. Thus, NKEF is a novel protein with unique amino acid sequence. Our results of NKEF in RBC suggest that RBC could play an important role in regulating NK function.

Amino Acid Sequence↗

PubMed1991

Cefotaxime-hydrolysing activity of the beta-lactamase of Klebsiella oxytoca D488 could be related to a threonine residue at position 140.

The chromosomally encoded beta-lactamase of Klebsiella oxytoca D483 strain, active against all third-generation cephalosporins but ceftazidime, was purified to homogeneity. The pure protein was digested by trypsin, Staphylococcus aureus V8 protease or proteinase Asp-N. Amino acid sequences of the HPLC-separated proteolytic peptides were determined by manual Edman degradation. Overlapping fragments gave the alignment of the 263 residues of the beta-lactamase which presented 90% homology with the beta-lactamase of the K. oxytoca E23004 strain and about 40% homology with the other enzymes of the structural class A. The cefotaximase activity might result from interaction of a threonine residue at position 140 (position 165 in the numbering of Ambler) with the oxyimino group of the antibiotic.

Amino Acid Sequence↗

PubMed2026

Microbiological analysis and whole-genome sequencing of Neisseria gonorrhoeae from the microbiological failures in the international, zoliflodacin, phase 3, clinical trial for treatment of uncomplicated urogenital gonorrhoea: a retrospective, genomic, observational study.

BACKGROUND: Zoliflodacin, a first-in-class oral bacterial, DNA gyrase (GyrB) inhibitor, showed non-inferiority to ceftriaxone combined with azithromycin in a recent large international, phase 3, randomised controlled trial for treatment of uncomplicated urogenital gonorrhoea. The aim of this study was to describe the microbiological and whole-genome sequencing (WGS) analyses of paired baseline (pre-treatment) and test-of-cure (TOC) gonococcal isolates from the zoliflodacin phase 3, randomised controlled trial to further characterise and evaluate the protocol-specified microbiological failures with zoliflodacin (n=22) or ceftriaxone and azithromycin (n=1). METHODS: In this retrospective, genomic, observational study, results from antimicrobial susceptibility testing (agar dilution method) of isolates (n=960; 936 baseline isolates from 763 participants and 24 TOC isolates [23 with a paired baseline isolate in the same anatomical site] from 20 participants) collected during the zoliflodacin phase 3, randomised controlled trial done in 16 outpatient clinics in Belgium, the Netherlands, South Africa, Thailand, and the USA (Nov 6, 2019-March 16, 2023) are described. WGS analysis was performed on paired baseline and TOC isolates from participants with microbiological failures (zoliflodacin 44 isolates [19 participants]; ceftriaxone and azithromycin two isolates [one participant]), and the three baseline isolates with highest zoliflodacin minimum inhibitory concentration (MIC 0·5 mg/L). FINDINGS: All isolates were inhibited by the same zoliflodacin concentrations (MICs ≤0·008 to 0·5 mg/L) as wild-type strains cultured internationally in 2013-23. In participants with a microbiological failure after zoliflodacin treatment (n=22, 19 participants), zoliflodacin MIC values for baseline and TOC isolates were similar, and resistance selection was lacking. WGS showed that five (23%) of 22 infections (95% CI 10-43 [in four participants]) of zoliflodacin microbiological failures had different strains at TOC versus baseline. In 17 zoliflodacin microbiological failures (15 participants), isolates at baseline and TOC were indistinguishable. 13 of these 17 microbiological failures, corresponding to 59% (95% CI 39-77; 13 of 22) of all zoliflodacin microbiological failures, were in urogenital or rectal sites in 11 participants and the isolates had zoliflodacin MICs less than or equal to 0·008 to 0·25 mg/L. The single microbiological failure after ceftriaxone and azithromycin treatment had different strains at TOC versus at baseline. No sequenced isolates had mutations associated with elevated zoliflodacin MICs. INTERPRETATION: In the zoliflodacin phase 3, randomised controlled trial, 23% of the zoliflodacin microbiological failures and the single ceftriaxone and azithromycin microbiological failure had different gonococcal strains at TOC versus baseline, which suggests reinfections and not treatment failures. In addition, 59% of the zoliflodacin microbiological failures, all in anogenital sites, had no obvious microbiological explanation based on the low zoliflodacin MICs, previous pharmacodynamic studies, and no evidence of resistance selection after zoliflodacin therapy. A reinfection as the cause for these microbiological failures could not be excluded. We recommend that WGS is implemented in future randomised controlled trials for gonorrhoea treatment to further evaluate possible microbiological failures, exclude reinfections (to avoid underestimating the cure rates), and characterise antimicrobial resistance determinants. FUNDING: GARDP through grants from Germany BMFTR (03KA1831), UK DHSC as part of GAMRIF, Japan MHLW, the Netherlands' Ministry of Health, Welfare and Sport and Directorate-General for International Cooperation, the Federal Office of Public Health of Switzerland, the Canton of Geneva, Switzerland, and Örebro University Hospital, Sweden.

Humans↗

PubMed1996

Specificity of antiparallel DNA triple helix formation.

We have used DNase I footprinting to examine the formation of antiparallel DNA triple helices on DNA fragments containing the homopurine target sites (GGA)2GGX(GGA)2GG.(CCT)2CCZ(CCT)2CC (where X.Z is each base pair in turn), with the GA- and GT-rich oligonucleotides, (GGA)2GGN(GGA)2GG and (GGT)2GGN(GGT)2GG (N = each base in turn). These were designed to form G.GC and A.AT or T.AT triplets with a central N.XZ mismatch, which should bind in an antiparallel orientation. We find that almost all combinations generate DNase I footprints at low micromolar concentrations. At each target site, the relative binding of the GA- and GT-containing oligonucleotides was not the same, suggesting that these two triplexes adopt different conformations. For a central GC base pair, the most stable complex is observed with a third strand generating a G.GC triplet as expected. A.GC is also stable, especially in the GT oligonucleotides. For a central AT base pair, all four bases form stable complexes though T.AT is favored for the GA-rich thirds strands and A.AT for the GT-rich strands. For a central CG base pair, the stable complexes are seen with third strands generating T.CG triplets, though A.CG and C.CG are stable with GT- and GA-containing oligonucleotides, respectively. C.TA is the best triplet at a central TA base pair. The third strands with central guanines avoided the formation of G.YR triplets on the fragments containing central pyrimidines, producing DNase I footprints which had slipped relative to the target site. These oligonucleotides bound at a different location, generating complexes containing 11 contiguous stable triplets at the 3'-end of the third strand. The results suggest rules for designing the best third strand oligonucleotides for targeting sequences in which homopurine tracts are interrupted by pyrimidines.

DNA↗

PubMed2002

HLA class I and II in black children with hepatitis B virus-associated membranous nephropathy.

BACKGROUND: The pathogenetic mechanisms by which individuals with chronic hepatitis B virus (HBV) infection develop membranous nephropathy (MN) are probably dependent on interactions between viral, host and environmental factors; some evidence suggests a genetic predisposition. HBVMN constitutes a major etiological group in black children with nephrotic syndrome. We therefore explored the HLA associations in black children with HBVMN. METHOD: Thirty black children, age range 2 to 16 years, with biopsy-proven HBVMN, were the subjects of the study. HBV status was determined using third generation ELISA. HLA A, B and C antigens were determined using a two-stage lymphocytotoxic test. HLA DRB1* and DQB1* typing was done using sequence-specific primers. HLA class 1 and II antigen frequencies of the study subjects were compared to controls that were randomly chosen healthy blood donors from the same population. RESULTS: HLA DQB1*0603 was increased in patients with HBVMN compared to controls (chi2 = 13.65, RR = 4.3). DRB1*07 and DQB1*02 were increased in frequency in the study subjects but failed to reach statistical significance. There was no significant difference in the frequencies of class 1 antigens in the study group compared to controls. CONCLUSION: To our knowledge, this is the first report of HLA associations in black patients with HBVMN in whom Class 1 and 11 antigens were determined using molecular methodology. There was a high frequency of DQB1*0603 in subjects compared to controls, suggesting a possible genetic predisposition to the development of HBVMN.

Adolescent↗

PubMed1993

Sub-minimum inhibitory concentrations of ceftibuten reduce adherence of Escherichia coli to human cells and induces formation of long filaments.

The minimal inhibitory concentrations (MICs) of an antibiotic are present for only a certain period of time, after which they become sub-inhibitory concentrations (sub-MICs). These sub-MICs are still active because they can interfere with the mechanism of bacterial adhesion, which is the first step in the sequence of events leading to infection. The purpose of the present study was to investigate the effects of sub-MICs of ceftibuten, a new third-generation cephalosporin, on the adhesion of Escherichia coli (E. coli) to human buccal cells. The degree of inhibition was maximal at 1/2 MIC and then gradually returned toward to the control values at 1/128 the MIC. The differences were statistically significant from 1/2 to 1/32 MIC. Since the MIC was 0.5 micrograms/ml, concentrations from 0.25 to 0.015 micrograms/ml significantly reduce bacterial adhesion. Ceftibuten also caused marked elongation of E. coli. These findings could help to explain the efficacy showed by ceftibuten in the treatment of respiratory and urinary tract infections when administered once daily.

Bacterial Adhesion↗

PubMed1993

Isolation and mapping of discrete DXS101 loci in Xq22 near the X-linked agammaglobulinaemia gene locus.

The X-linked agammaglobulinaemia (XLA) gene locus has previously been mapped to Xq22 in genetic linkage studies. The DXS101 locus has shown no recombinations with XLA in the ten informative meioses investigated so far. The DXS101 sequence, recognised by the cX52.5 plasmid, is moderately repeated in Xq22. We have isolated cosmids which contain this sequence; two copies of which have been found to lie near DXS178 and XLA, and a third copy which lies near the PLP gene, distal to these loci. We have used the cosmids to generate probes which should be of use for RFLP analysis, and thus in both prenatal diagnosis and carrier testing for XLA, and in constructing a genetic map of this region. These probes will also be used to complement the genetic map in the construction of a complete physical map of Xq22.

Agammaglobulinemia↗

PubMed1988

Length polymorphisms in human proline-rich protein genes generated by intragenic unequal crossing over.

Southern blot hybridization analysis of genomic DNAs from 44 unrelated individuals revealed extensive insertion/deletion polymorphisms within the BstNI-type loci (PRB1, PRB2, PRB3 and PRB4) of the human proline-rich protein (PRP) multigene family. Ten length variants were cloned, including alleles at each of the four PRB loci, and in every case the region of length difference was localized to the tandemly repetitious third exon. DNA sequences covering the region of length variation were determined for seven of the alleles. The data indicate (1) that the PRB loci can be divided into two subtypes, PRB1 plus PRB2, and PRB3 plus PRB4, and (2) that the length differences result from different numbers of tandem repeats in the third exons. Variant chromosomes were also identified with different numbers of PRP loci resulting from homologous but unequal exchange between the PRB1 and PRB2 loci. The overall data are compatible with the observed length variants having been generated via homologous but unequal intragenic exchange. The results also indicate that these crossover events are sensitive to the amount of homology shared between the interacting DNA strands. Allelic length variants have arisen independently at least 20 times at the PRB loci, but only one has been detected at a PRH locus. Comparison of the detailed structures of the repetitious regions in PRB and PRH loci shows that the repeats in PRB genes are very similar to each other in sequence and in length. The PRH genes contain fewer repeats, which differ considerably in their individual lengths. These differences suggest that the larger number of length variants in PRB genes is related to their greater ease of homologous but unequal pairing compared to PRH genes.

Alleles↗

PubMed2025

Biallelic antigen escape is a mechanism of resistance to anti-CD38 antibodies in multiple myeloma.

Monoclonal antibodies targeting CD38 are a therapeutic mainstay in multiple myeloma (MM). Although they have contributed to improved outcomes, most patients still experience disease relapse, and little is known about tumor-intrinsic mechanisms of resistance to these drugs. Antigen escape has been implicated as a mechanism of tumor-cell evasion in immunotherapy. Yet, it is unknown whether MM cells can develop permanent resistance to anti-CD38 antibodies by acquiring genomic events leading to biallelic disruption of the CD38 gene locus. Here, we analyzed whole-genome and whole-exome sequencing data from patients 701 newly diagnosed MM, 67 patients at relapse with naivety to anti-CD38 antibodies, and 50 patients collected at relapse after anti-CD38 antibodies. We report a loss of CD38 in 10 of 50 patients (20%) after CD38 therapy, 3 of whom exhibited a loss of both copies. Two of these cases showed convergent evolution in which distinct subclones independently acquired similar advantageous variants. Functional studies on missense mutations involved in biallelic CD38 events revealed that 2 variants, L153H and C275Y, decreased binding affinity and antibody-dependent cellular cytotoxicity of the commercial antibodies daratumumab and isatuximab. However, a third mutation, R140G, conferred selective resistance to daratumumab, while retaining sensitivity to isatuximab. Clinically, patients with MM are often rechallenged with CD38 antibodies after disease progression and these data suggest that next-generation sequencing may play a role in subsequent treatment selection for a subset of patients.

Humans↗

PubMed2002

Frequent occurrence of the T-loop RNA folding motif in ribosomal RNAs.

Analysis of atomic resolution structures of the rRNAs within the context of the 50S and the 30S ribosomal subunits have revealed the presence of nine examples of a recurrent structural motif, first observed in the TpsiC loop of tRNAs. The key component of this T-loop motif is a UA trans Watson-Crick/Hoogsteen base pair stacked on a Watson-Crick pair on one side. This motif is stabilized by several noncanonical hydrogen bonds, facilitating RNA-RNA as well as RNA-protein interactions. In particular, the sugar edge of the purine on the 3' side of the pivotal uridine in the UA pair frequently forms a noncanonical base pair with a distant residue. The bulged-out bases, usually seen as part of the motif, also use their Watson-Crick edges to interact with nearby residues via base-specific hydrogen bonds. In certain occurrences, a backbone reversal is stabilized by specific hydrogen bonds as is observed in the U-turn motifs and the adenosine residue of the key UA pair interacts with a third base via its Watson-Crick edge, essentially generating a base triple.

Base Pairing↗

PubMed2000

Three different turkey luteinizing hormone receptor (tLH-R) isoforms I: characterization of alternatively spliced tLH-R isoforms and their regulated expression in diverse tissues.

Using combinations of reverse transcription-polymerase chain reaction (RT-PCR) and 5'- and 3'-rapid amplification of cDNA ends, three different, alternatively spliced, partial turkey LH receptor (tLH-R) cDNA isoforms were characterized from ovarian mRNA. The first cDNA (tLH-R(intact)) showed 98% and 72-75% similarity with chicken and mammalian LH-R sequences, respectively. The second cloned cDNA isoform (tLH-R(insert)) contained an in-frame TGA stop codon within an 86-base pair insertion that was located in the extracellular domain of the seven-transmembrane region. The tLH-R(insert) isoform could encode a truncated soluble protein isoform that lacked the transmembrane region. The third cDNA isoform truncated the transmembrane region (tLH-R(trunc)) and was derived by the deletion of the last exon by incomplete splicing. Generation of multiple transcripts by alternative splicing was elucidated by partial characterization of tLH-R genomic sequences. The differentially regulated expression of the tLH-R mRNA isoforms in nongonadal tissues and ovarian stromal tissues during various reproductive stages was quantified and analyzed by Northern blot and/or RT-PCR. Alternatively spliced tLH-R isoforms were differentially expressed in a tissue-specific manner in most of the tissues examined. The steady-state levels of tLH-R mRNA isoforms were relatively high in the hypothalamus and optic nerve and relatively low in the cortex, pituitary, and cerebellum when compared to levels in ovarian follicles. In nongonadal reproductive tissues, the steady-state levels of tLH-R mRNA isoforms were relatively high in the uterus and infundibulum and relatively low in the isthmus, oviduct, and magnum. In addition, in the nongonadal peripheral tissues, the steady-state levels of tLH-R isoforms were relatively high in the thyroid gland and relatively low in the spleen, adrenal gland, kidney, skin, bursa, and muscle. The present study suggests that the alternative splicing of LH-R transcripts occurs in a tissue-specific manner and has been evolutionarily conserved (similar results were obtained in chicken and swine). These results raise fundamental questions as to the function of LH-R isoforms in nongonadal tissues.

Alternative Splicing↗