Theses and Dissertations - UTB/UTPA

Date of Award


Document Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Anxiu Kuang

Second Advisor

Dr. Qingyi Yu

Third Advisor

Dr. Luis Materon


All organisms face DNA-damaging radiation in the form of UV light and must have mechanisms to repair or undo damage. Plants being stationary organisms must cope with damaging UV rays in a molecular fashion and so have developed many forms of resistance. MMS19 is implicated in DNA repair indirectly as a nuclear encoded gene that binds onto protein assembly complexes in the cytosol. A mutant within the SunUp variety of Carica papaya has a large deletion for MMS19 and presents a diminutive phenotype. Deficient DNA repair mechanisms will shunt cells out of the natural cell cycle and reduce cell proliferation and differentiation. In this study the diminutive phenotype was characterized using electron microscopy, fluorescent microscopy, and RT-PCR. Mutant cells within leaf tissues showed increased autolytic and apoptotic activity, reduced expression of downstream genes indicating that MMS19 is necessary for maintaining normal growth and development of papaya.


Copyright 2015 Jorge A. Trujillo. All Rights Reserved.

Granting Institution

University of Texas-Pan American