Misalignment of V and J gene segments resulting in a nonfunctional immunoglobulin gene.

The myeloma variant NS-1n has lost the functional immunoglobulin kappa gene which is present in its parent, myeloma MOPC-21. The variant retains a nonfunctional rearranged gene, M.21N, which undergoes RNA transcription and processing to yield a mature size kmRNA. This kRNA, however, is not translated into kappa polypeptide chains. The nonfunctional gene was cloned into Charon 4A to determine the basis for its inactivity. Nucleotide sequence analysis of a DNA fragment overlapping the V-J recombination site in the M.21N gene indicated that a misalignment had taken place during somatic recombination. This misalignment results in a deletion of four nucleotides at the 3' end of the V gene and, thus, a translational reading frame shift. In other respects the M.21n V gene, which corresponds to a different VK subgroup than the functional gene of MOPC-21, appears normal

Comparison of different rearranged immunoglobulin kappa genes of a myeloma by electronmicroscopy and restriction mapping of cloned DNA: implications for "allelic exclusion".

We have studied the organization and function of different rearranged kappa genes in a myeloma, MOPC-21. Two kappa genes were cloned into Charon 4A and compared with each other and with a cloned germline CK gene by restriction mapping and electron microscopy. One MOPC-21 clone corresponds to the gene coding for the MOPC-21 kappa chain polypeptide; it has the V21 gene joined with the CK gene at the J2 sequence. The other MOPC-21 clone corresponds to a nonfunctional rearranged MOPC-21 kappa gene, except for a lkb deletion, 3' of J4. A similar deletion is also found in a "new" kappa gene present in NS-1, a cellular subclone of MOPC-21. The clone of the "nonfunctional" kappa gene has a V gene which is distinct from V21 which is joined to CK in the vicinity of J2. The undeleted form of this gene codes for a KRNA having the size of mature KmRNA which, however, is not translated into kappa chains. Thus the defect of the "nonfunctional" gene manifests itself at a late step of gene expression. The basis for "allelic exclusion" of antibody genes may simply be the complexity of the processes between genes and gene products, resulting in the expression of only one gene

Lung Physiological Variations in COVID-19 Patients and Inhalation Therapy Development for Remodeled Lungs

In response to the unmet need for effective treatments for symptomatic patients, research efforts of inhaled therapy for COVID-19 patients have been pursued since the pandemic began. However, inhalation drug delivery to the lungs is sensitive to the lung anatomy and physiology, which can be significantly altered due to the viral infection. The ensued ventilation heterogeneity will change distribution and thus dosimetry of inhaled medications, rendering previous correlations concepts? of pulmonary drug delivery in healthy lungs less reliable. In this study, we first reviewed the recent developments of inhaled therapeutics and vaccines, as well as the latest knowledge of the lung structural variations documented by CT of COVID-19 patients\u27 lungs. We then quantified the volume ratios of the poorly aerated lungs and non-aerated lungs in eight COVID-19 patients, which ranged 2-8% and 0.5-3%, respectively. The need to consider the diseased lung physiologies in estimating pulmonary delivery was emphasized. Diseased lung geometries with varying lesion sites and complexities were reconstructed using Statistical Shape Modeling (SSM). A new segmentation method was applied that could generate patient-specific lung geometries with an increased number of branching generations. The synergy of the CT-based lung segmentation and SSM-based airway variation showed promise for developing representative COVID-infected lung morphological models and investigating inhalation therapeutics in COVID-19 patients

Structural similarity between the lepidoptera- and diptera-specific insecticidal endotoxin genes of Bacillus thuringiensis subsp. "kurstaki" and "israelensis".

A gene from Bacillus thuringiensis subsp. "israelensis" was cloned from the large plasmids of this subspecies and was shown to code for a mosquitocidal polypeptide. The gene could be expressed in either Escherichia coli, Bacillus subtilis, or B. thuringiensis subsp. "israelensis" to produce the larvicidal activity. Similarly, a Lepidoptera-specific toxin gene from B. thuringiensis subsp. "kurstaki" was also cloned and expressed in E. coli and B. subtilis. Both cloned genes were sequenced and subjected to computer analysis. A long open translational reading frame coded for the B. thuringiensis subsp. "kurstaki" gene product. However, the B. thuringiensis subsp. "israelensis" clone was composed of two adjacent open reading frames oriented as if they were in a transcriptional operon. The products of the cloned genes retained their specificity for either Lepidoptera or Diptera. The control regions immediately preceding the toxin genes of both B. thuringiensis subspecies showed considerable DNA homology, most likely because both toxins are expressed only during sporulation. In addition, the deduced amino acid sequences from the two contiguous B. thuringiensis subsp. "israelensis" genes bore a striking resemblance to the deduced amino acid sequence from the single larger B. thuringiensis subsp. "kurstaki" gene, as if these two arrangements were evolutionarily related