Publications by authors named "Rajesh Gaur"

Background And Objectives: Exploring the disease profile in a defined area helps policymakers to understand local health issues. It is essential to collect such information in countries, like India, which have a wide range of socioeconomic, geographic, and cultural diversity. Madhya Pradesh is the second largest state of India and has diversified populations living in urban, rural, and tribal areas.

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Hereditary persistence of fetal hemoglobin (HPFH) is a benign condition in which significant fetal hemoglobin production continues well into adulthood, disregarding the normal shutoff point after which only adult-type hemoglobin should be produced. The percentage of incorrect expression might be as low as 10%-15% or as high as 100% of the total hemoglobin, usually higher in homozygotes than in heterozygotes. The present case is a typical example of homozygous HPFH.

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COVID-19 is an infectious respiratory disease caused by SARS-CoV-2, a new beta coronavirus that emerged in Wuhan, China. Being primarily a respiratory disease, it is highly transmissible through both direct and indirect contacts. It displays a range of symptoms in different individuals and thus has been grouped into mild, moderate, and severe diseases.

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We investigated the association of LHR expression in epithelial ovarian cancer (OC) with clinical and pathologic characteristics of patients. LHR expression was examined immunohistochemically using tissue microarrays (TMAs) of specimens from 232 OC patients. Each sample was scored quantitatively evaluating LHR staining intensity (LHR-I) and percentage of LHR (LHR-P) staining cells in tumor cells examined.

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Carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) is expressed in a variety of cell types and is implicated in carcinogenesis. Alternative splicing of CEACAM1 pre-mRNA generates two cytoplasmic domain splice variants characterized by the inclusion (L-isoform) or exclusion (S-isoform) of exon 7. Here we show that the alternative splicing of CEACAM1 pre-mRNA is regulated by novel cis elements residing in exon 7.

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HIV-1 infection is the cause of acquired immune deficiency syndrome (AIDS). Highly active antiretroviral therapy (HAART) has been successful in reducing the rate of progression to AIDS, but a cure has not yet been achieved. New tools are required to delay progression of infection or to block the replication cycle of HIV.

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The majority of eukaryotic genes undergo alternative splicing, an evolutionarily conserved phenomenon, to generate functionally diverse protein isoforms from a single transcript. The fact that defective pre-mRNA splicing can generate non-functional and often toxic proteins with catastrophic effects, accurate removal of introns and joining of exons is vital for cell homeostasis. Thus, molecular tools that could either silence a disease-causing gene or regulate its expression in trans will find many therapeutic applications.

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Ultraviolet (UV)-dependent photochemical crosslinking is a powerful approach that can be used for the identification of RNA-protein interactions. Although 8-azidoATP (8-N(3)ATP) has been widely used to elucidate the ATP binding site of a variety of proteins, its inability to serve as an efficient substrate for bacteriophage RNA polymerases apparently restricted its actual potential as a photocrosslinking agent. In this chapter, in vitro transcription conditions that allow for template-dependent incorporation of 8-N(3)AMP into RNA are described.

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Background: Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), a cell adhesion molecule expressed in a variety of cell types is a putative tumor suppressor gene. Alternative splicing of CEACAM1 generates 11 different splice variants, which include 1-4 ectodomains with either short or long cytoplasmic domain generated by the exclusion (CEACAM1-S) or inclusion (CEACAM1-L) of exon 7. Studies in rodents indicate that optimal ratios of CEACAM1 splice variants are required to inhibit colonic tumor cell growth.

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Despite the important role of alternative splicing in various aspects of biological processes, our ability to regulate this process at will remains a challenge. In this report, we asked whether a theophylline-responsive riboswitch could be adapted to manipulate alternative splicing. We constructed a pre-mRNA containing a single upstream 5' splice site and two 3' splice sites, of which the proximal 3' splice site is embedded in theophylline-responsive riboswitch.

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Background: Despite tremendous progress in understanding the mechanisms of constitutive and alternative splicing, an important and widespread step along the gene expression pathway, our ability to deliberately regulate gene expression at this step remains rudimentary. The present study was performed to investigate whether a theophylline-dependent "splice switch" that sequesters the branchpoint sequence (BPS) within RNA-theophylline complex can regulate alternative splicing.

Results: We constructed a series of pre-mRNAs in which the BPS was inserted within theophylline aptamer.

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Alternative splicing of precursor messenger RNAs (pre-mRNAs) is one of the most important sources of protein diversity in vertebrates. An estimated 35%-70% of human genes generate transcripts that are alternatively spliced, and defects in this process are linked to numerous human genetic diseases and various forms of cancer. The discovery that 21-23 nucleotide RNA duplexes, known as small interfering RNAs (siRNAs), can knockdown the homologous mRNAs in mammalian cells has revolutionized many aspects of drug discovery including down-regulation of disease-associated splicing isoforms.

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Riboswitches, as previously reported, are natural RNA aptamers that regulate the expression of numerous bacterial metabolic genes in response to small molecule ligands. It has recently been shown that these RNA genetic elements are also present near the splice site junctions of plant and fungal introns, thus raising the possibility of their involvement in regulating mRNA splicing. Here it is shown for the first time that a riboswitch can be engineered to regulate pre-mRNA splicing in vitro.

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UV-induced photochemical crosslinking is a powerful approach that can be used for the identification of specific interactions involving nucleic acid-protein and nucleic acid-nucleic acid complexes. 8-AzidoATP (8-N(3)ATP) is a photoaffinity-labeling agent which has been widely used to elucidate the ATP binding site of a variety of proteins. However, its true potential as a photoactivatable nucleotide analog could not be exploited due to the lack of 8-azidoadenosine phosphoramidite, a monomer used in the synthesis of RNA, and the inability of 8-N(3)ATP to serve as an efficient substrate for bacteriophage RNA polymerase.

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The potential of standard in vitro transcription reactions can be dramatically expanded, if chemically synthesized low-mol-wt compounds are used as building blocks in combination with standard nucleotide 5' triphosphates (NTPs). Short oligonucleotides that terminate in guanosine effectively compete with guanosine 5' triphosphate (GTP) as starter building blocks, and they are incorporated at the 5'-end of transcripts. Applications include production of RNAs with "unfriendly 5'-ends" (they do not begin with G), variations of the 5'-sequence are possible with the same DNA template, site-specific insertion of nucleotide modifications, and addition of 5'-labels, such as fluorescein for detection or biotin for capture.

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