Lon S Kaufman - US grants

The overall goal of this research is to identify factors involved in blue-light induced transcription of proteins in higher plants. There are two basic classes of transcription factors, core factors and regulatory factors. Core factors allow for low level, constitutive expression. Their presence or activity is not regulated and they function for many genes. Regulatory factors are not always active and affect the rate of Pisum sativum (pea) and Arabidopsis thaliani to identify the regulatory factors that effect blue-light transcription of a pigment-binding protein found in plants. Blue light represents a regulatory signal for many events in growth and development. Examples of these events are found in all the kingdoms and range from bacterial motion to alleviation of winter depression in humans. The basic biochemical mechanism by which blue light is perceived and transduced into a signal useful for the cell is probably very ancient. Indeed, as light represents one of the oldest environmental cues, it may be that blue-light regulation is the oldest signal. Understanding this ancient mechanism will provide insight into how cells interpret many extracellular signals.

The process of RNA destabilization is known to be of equal importance to transcription in the regulation of gene expression. In direct contrast to its pivotal role in gene expression, the biochemistry and developmental regulation of the biochemistry of destabilization is very poorly understood. This lack of understanding is even greater for plants and even greater still for 5'-UTR (untranslated region) mediated destabilization. Activation of the Blue High Fluence (BHF) system results in the destabilization of several specific transcripts including the PsLhcb1*4 and At Lhcb1*3 transcripts. The response is not the result of stress, occurs rapidly, and does not require protein synthesis. The destabilization element resides wholly in the 5'-UTR. Previous studies in this investigator's laboratory have focused on defining the photobiology and phenomenology of the BHF-system mediated destabilization, which has provided a very solid base of data establishing and describing the destabilization response and its relation to other cellular, developmental and photobiological and clock processes including:

The BHF-system-destabilization element resides wholly within the respective 5'-UTR.

The destabilization mechanism may be similar, if not identical, to that responsible for stability and/or processing of rbcL and other chloroplast encoded transcripts.

The ability of the BHF system to function is developmentally regulated and represents a classic case of developmental competence.

The destabilization event triggered by excitation of the BHF system is also subject to regulation by the circadian clock.

NPH1, the blue-light activated kinase that functions as the photoreceptor for phototropic curvature, is the photoreceptor for the BHF system.

The proposed experiments are designed to build upon these observations. All of the proposed experiments will focus on the BHF system mediated destabilization. None of the experiments requires development of new technology, and all can be initiated immediately or are already under way. Four specific aims will be addressed:

Identification of the sequence elements and structures present in the PsLhcb1*4 5'-UTR responsible for BHF system mediated (and clock regulated) destabilization.

Subcellular localization of the BHF system mediated destabilization event(s) in pea and in Arabidopsis.

Identification of RNA-binding and RNase activities associated with the BHF response.

Genetic and molecular genetic testing of existing blue-light signaling mutants and genes for BHF system activity/NPH1 as a potential photoreceptor.

The Assuring Stem Credential Expansion through Nurturing Diversity (ASCEND) project is increasing the number of students earning undergraduate degrees in science, technology, engineering, and mathematics (STEM) with special emphasis on retaining and graduating women and minorities. The university has been successful at enrolling students into STEM disciplines but attrition rates are high. ASCEND is addressing this loss of talent through coordinated, mutually reinforcing activities that transform the vulnerable first-year STEM experience.

The intellectual merits of ASCEND include the team's approach to developing and utilizing a dynamic model (one that incorporates national best practices for recruiting and retaining underrepresented STEM students) and a careful and thorough evaluation of its impact. In concert with this, ASCEND is enabling a cadre of highly-committed faculty, advisors, and top administrators to execute four strategies: create an ASCEND Learning Community for STEM freshman; increase the quality and relevance of STEM teaching through a Community of Practice; strengthen STEM support units and Learning Centers and foster collaboration; and build institutional capacity to capture, track, and report on the academic trajectories of STEM students.

ASCEND's broader impacts include improved retention and graduation rates in science, technology, engineering, and mathematics (STEM) for women and minorities. These graduate scientists and engineers are lending their perspectives and talents to the local and national STEM workforce. The ASCEND model also is informing efforts at other comparable institutions, and is having an impact by increasing diversity and gender equity in STEM.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

Scientific Merit: Seedlings have little or no protection against non-biotic stresses present in the environment (i.e. heat, ultraviolet sunlight [UV], salt, etc). The initial components of the sensing mechanisms that control tolerance to specific stresses remain unknown. It is therefore important to develop an understanding of how signal transduction systems within the seedling are activated by environmental stresses. The project will study the signal transduction system(s) that operates to produce the amino acid phenylalanine. Phenylalanine in turn serves as the precursor to many compounds that have a role in protecting plants against environmental stress. This signal transduction system appears to act in concert with several plant hormones known to have a role in how plants respond to environmental stress. The research will be conducted using Arabidopsis, a model plant organism, wherein each step of the signaling pathway that leads to the synthesis of the amino acid phenylalanine can be studied in detail.

Broader Impact. Dissecting and understanding a simple stress-induced signaling pathway allows for the participation of undergraduate students as researchers and as authors on publications. Understanding this basic "stress cassette" in a young plant will allow researchers to evaluate many stresses with respect to their signaling pathways, their relationship to known stress-reported plant hormones and the specific compounds they direct the plant to produce. This is an important broader impact as much of crop loss worldwide arises from stresses incurred within the first two weeks after seeds are planted. The available arable land, both urban and rural, is decreasing, and the levels of environmental stressors are greater than ever before. Understanding how stresses are perceived is relevant for crop breeding, crop productivity, range management and the propagation of healthier foodstuffs.