Techniques Used in Expression Patterns, Mutations, and Interaction - Literature review Example

Literature Review By Devangini Mahapatra Chauhan The study of genetics and biotechnology, among a plethora of others have invariably come up with various modes of defining expression patterns through the study of mutations and interactions in plasmas, cells and genes. Primarily used in the study of genetics and other related fields, expression patterns form the basis for the analysing complementary domains of multimeric distributions in plasma. Mutation and interaction, on the other deal with the correlation of factors in fields like development neurobiology through the study of mammalian neurogenesis. In this paper, I will seek to provide the relevant literature that deals with four articles that have been written in this context, with special emphasis on the techniques used in each of them. The literature review in this matter will be exhaustive in context of widespread literary work in this regard. The first article is titled Regulation of CLV3 Expression by Two Homeobox Genes in Arabidopsis. It has been written by Ulrike Brand, Margit Grunewald, Martin Hobe and Rudiger Simon. This article primarily deals with the nuances of clavata regulation where it starts with the observation that the constant creation of new and renewed organs will depend greatly on the qualitative and quantitative elements of the stem cell populations which are closely linked with the competence and ability of meristems. (Brand et al, 2002) This brings to the fore the technique used by the regulation in context of negative feedback regulation between the two pathways in promoting or restricting stem cell quantities. This technique revolves around the use of a promoter and has been written about in the context of genetic background by Isabel Baurle and Thomas Laux, in their article titled, Regulation of WUSCHEL Transcription in the Stem Cell Niche of the Arabidopsis Shoot Meristem. In this article, they have studied variations of the studies put down by Brand et al, in context of genetic backgrounds. These studies revolve around the assumption that specialised environments promote the localisation of pluripotent cells by defining the various pathways leading to interrelations. According to the writers, there interrelations have to do with the transcriptional control of the WSU cell, in acting as a promoter to learn more about the regulations within cellular boundaries. (Baurle, et al, 2005) There is also a question of whether or not ectopic STM expression is sufficient as a promoter in order to lead to the activation of CLV3 in non – meristematic tissues, where there is a review of the CaMV35S promoter in highly disorganised shoot meristem activities which threaten to curb development at the early seeding stage itself. (Brand et al, 2002) In this context, the work produced by M K Barton and R S Poethig titled , Formation of the shoot apical meristem (in Arabidopsis thaliana: an analysis of development in the wildtype and in the shoot meristemless mutant) talks of the role of a promoter where shoot apical meristem formations are concerned. This article primarily deals with the nuances of apical meristem in a bid to find the regulations that may be adapted to find pathways for the study of shoot development through the context of mutation and interaction of the same. (Barton et al, 1993) Further, it has been found the boundaries of WUS transcription in the shoot meristem stem cell niche can be controlled through the use of other components in the meristem composition. For doing so, one would have to typically make use of a 57-bp regulatory region. In this regard, this activity can be further assigned to two adjacent short sequence motifs. When placed within this region. This process further assists the promoter in the regulation activity. (Sablowski, 2007) This has been suggested by Robert Sablowski in the article titled, Flowering and determinacy in Arabidopsis. In this regard, the author has defined the role of the promoter as one that supports findings that imply an integration that takes place at a point where the two short sequence elements of the WUS promoter meet. This in turn deals with the diverse regulatory pathways that control the stem cells in the shoot meristem integration points. This goes on to suggest that the mutation of regulatory formulations has a focus in the level of a central transactivating complex. (Sablowski, 2007) Further, in context of defining the parameters within which this promoter works, it has been observed that the constant activity of producing new cells which will facilitate the growth and development of new organs as long as the plant lives is widely dependant on the regulatory genes that balance the proliferation of meristem cells. These genes carry out this activity with their recruitment to organogenesis within the contextual framework of the promoter. Therefore, this balance has been seen to shifting focus towards organogenesis in the course of flower development. This shift in balance leads to a termination of the meristem once it has produced a number of organs that are genetically determined. (Sablowski, 2007) Considering the fact that article by Brand et al revolves around a special emphasis on Arabidopsis, WUSCHEL (WUS) as the promoter, it would be imperative to link this with Sablowski’s work where he discusses self renewing cells. In his article, Sablowski specifies that at the centre of the activities representing changes in the shoot merisetm, one will find self-renewing cells. Also, he further goes on to define these cells as the key target in the control of meristem stability. (Sablowski, 2007) Therefore, the results of this process show how the APETALA1/CAULIFLOWER (AP1/CAL) and LEAFY (LFY) carry out the process of activating the development of a particular floral meristem. (Sablowski, 2007) In this context, while LFY activates AGAMOUS (AG) in co-operation with WUS, AG follows up by guiding the development of the innermost floral organs. (Sablowski, 2007) Simultaneously, one will find that this process antagonizes WSU and it even threatens to terminate the meristem. In this regard, there is still much to be know in order to effectively study the mechanism of termination carried out by WUS, which offers a wider scope for research and analysis. (Sablowski, 2007) This brings to the next article. Titled KNAT1 Induces Lobed Leaves With Ectopic Meristems when Overexpressed in Arabidopsis, this article has been written by George Chuck, Cynthia Lincoln and Sarah Hake. This work deals primarily with the technique of overexpression in Arabidopsis in context of etopic meristems. Considering the fact that this work studies the development of lobed leaves, the overexpression degree has been quantified by KNAT1. (Chuck et al, 1996) This article starts out by defining plant development processes in terms of apical meristems, which further have a potential role in the activities surrounding the homeobox. This shows a strong connection with the promoters used in clavata regulation in the sense that it identifies whether the meristem is vegetative pr floral, and thus supports the initiations of lobes into points of serration. (Chuck et al, 1996) Therefore, in terms of leaf development, the authors have cited the origins of the same through arabidopsis in context of organ development and the tissues that support the same. In this context, the book titled Transgenic Plants in Agriculture – Ten Years Experience of the French Biomolecular Engineering Commission, by Alex Kahn, demonstrates the nuances of the development of these lobes and leaves in the fifth chapter titled, ‘The creation of transgenic plants’. This chapter discusses the morphological differences in the leaves that promote subtle heteroblastic development. This showcases how overexpression leads to the formation of the primary leaves which seek to terminate the veins in the succeeding serrations. (Kahn 1999) This brings us to a discussion of the third article which revolves around knox interactions through the technique of yeast two – hybrid method. Titled The Arabidopsis BELL1 and KNOX TALE Homeodomain Proteins Interact through a Domain Conserved between Plants and Animals, this article has been written by Mohammed Bellaoui, Mark S. Pidkowich, Alon Samach, Kumuda Kushalappa, Susanne E. Kohalmi, Zora Modrusan, William L. Crosby, and George W. Haughn, for the Botany Department and Biotechnology Laboratory. According to Paul L Bartel’s book titled The Yeast Two Hybrid System, this method which is more popularly know as Y2H, is part of the development by Stan Fields as a technique to tap into the nuances of protein-protein interactions. While this method may still require work owing to the fact that it is not foolproof, the main area where it adheres to the plant and animal domain is through a study of protein interactions. The weakness of this technique lies in the fact that it does allow high throughput screening of protein interactions. This has been considered a weakness owing to the fact that screening of protein interactions has been considered as a critical component of proteomics. (Bartel, 1997) In the article by Bellaoui et al, demonstrates the interactions between TALE (three–amino acid loop extension) homeodomain proteins and how the level and quality of these interactions play important roles in the development of both fungi and animals. (Bellaoui et al, 2001) Embedded into these observations is the Y2H method, which works to indicate the interactions between shoot meristemless expressions in context of infloroscence meristem. This further goes to introduce a key element in the form of BEL1 – STM. This brings us to the final article which is titled A Member of the KNOTTED Class of Homeodomain Proteins Encoded by the STM Gene of Arabidopsis. Written by Jeff A Long, Erich I Moan, June I Medford and M Kathryn Barton, this work explores technique of forward genetics which supports the evidence that suggests the context of knotted plants in the study of the shoot merisetm function. In this regard, the primary assumption is that all mutant phenotypes have been linked effectively with genes that revolve around gain – of – function mutations. While this creates difficulties in the determination of their wild type functions, it also demonstrates the fact that the regulatory genes often give rise to diametrically opposite phenotypes. (Long et al, 1996) In this context, the book RNA Interference Technology: From Basic Science To Drug Development by Andrew (FRW) Fire, Marshall (FRW) Nirenberg, Appasani, Krishnarao. Appasani describes forward genetics in context of the knotted like gene in Arabidopsis called the meriHB1 cDNA. In the case of forward genetics for regulation and phenotypes, this has been studied to find the genomic DNA sequence corresponding to knotted like gene. Further, in this book, the forward genetic treatment has been represented as a traditional genetic approach. According to this approach, analysis starts with a mutation phenotype and works toward identification of the mutated gene. (Fire et al, 2005) References: 1. Fire, Andrew (FRW); Nirenberg, Marshall (FRW); Appasani, Krishnarao. Appasani (2005) RNA Interference Technology: From Basic Science To Drug Development. Cambridge University Press. 2. Brand, Ulrike; Grunewald, Margit; Hobe, Martin; Simon, Rudiger (June 2002) Regulation of CLV3 Expression by Two Homeobox Genes in Arabidopsis. Plant Physiology, Vol 129 3. Baurle, Isabel; Laux, Thomas (June, 2005). Regulation of WUSCHEL Transcription in the Stem Cell Niche of the Arabidopsis Shoot Meristem. American Society of Plant Biologists. 4. Barton, M. K; Poethig, R. S (1993) Formation of the shoot apical meristem. Arabidopsis thaliana: an analysis of development in the wildtype and in the shoot meristemless mutant. 5. Sablowski, R. (2007). Flowering and determinacy in Arabidopsis. Society of Experimental Biology. Oxford University Press. 6. Chuck, G; Lincoln, C; Hake, S (August 1996) KNAT1 Induces Lobed Leaves With Ectopic Meristems when Overexpressed in Arabidopsis. American Society of Plant Physiologists. 7. Long, Jeff A; Moan, Erich I; Medford, June I; Barton, M Kathryn (November, 2001) A Member of the KNOTTED Class of Homeodomain Proteins Encoded by the STM Gene of Arabidopsis. The Plant Cell, American Society of Plant Biologists. 8. Kahn, A (1999) Transgenic Plants in Agriculture – Ten Years Experience of the French Biomolecular Engineering Commission. John Libbey Eurotext. 9. Bellaoui, M; Pidkowich, M. S; Samach, A; Kushalappa, K; Kohalmi, S. E; Modrusan, Z; Crosby, W. L; Haughn, G. W. (2001) The Arabidopsis BELL1 and KNOX TALE Homeodomain Proteins Interact through a Domain Conserved between Plants and Animals. The Botany Department and Biotechnology Laboratory. 10. Bartel, P. L (1997). The Yeast Two Hybrid System. Oxford University Press, US. Read More