A possible meiotic function of the peculiar patterns of gene expression in mammalian spermatogenic cells
نویسنده
چکیده
This review focuses on the striking differences in the patterns of transcription and translation in somatic and spermatogenic cells in mammals. In early haploid cells, mRNA translation evidently functions to restrict the synthesis of certain proteins, notably protamines, to transcriptionally inert late haploid cells. However, this does not explain why a substantial proportion of virtually all mRNA species are sequestered in translationally inactive free-messenger ribonucleoprotein particles (free-mRNPs) in meiotic cells, since most mRNAs undergo little or no increase in translational activity in transcriptionally active early haploid cells. In addition, most mRNAs in meiotic cells appear to be overexpressed because they are never fully loaded on polysomes and the levels of the corresponding protein are often much lower than the mRNA and are sometimes undetectable. A large number of genes are expressed at grossly higher levels in meiotic and/or early haploid spermatogenic cells than in somatic cells, yet they too are translated inefficiently. Many genes utilize alternative promoters in somatic and spermatogenic cells. Some of the resulting spermatogenic cell-altered transcripts (SCATs) encode proteins with novel functions, while others contain features in their 5'-UTRs, secondary structure or upstream reading frames, that are predicted to inhibit translation. This review proposes that the transcriptional machinery is modified to provide access to specific DNA sequences during meiosis, which leads to mRNA overexpression and creates a need for translational fine-tuning to prevent deleterious consequences of overproducing proteins.
منابع مشابه
P-230: Analysis of TEX15 Expression in Testis Tissues of Severe Oligozoospermic and Non-Obstructive Azoospermic Men Referred to Royan Institute
Background: TEX15 is a novel protein that is required for chromosomal synapsis and meiotic recombination. Human TEX15 is located on chromosome 8(8p12 region) and expressed in testis and ovary, as is its mouse ortholog. Loss of TEX15 function in mice causes early meiotic arrest in males but not in females. Specifically, TEX15 deficient spermatocytes exhibit a failure in chromosomal synapsis. In ...
متن کاملEnhancement of RNA Interference Effect in P19 EC Cells by an RNA-dependent RNA Polymerase
Background: RNA interference (RNAi) is a phenomenon uses double-stranded RNA (dsRNA) to specifically inhibit gene expression. The non-specific silencing caused by interferon response to dsRNA in mammalian cells limits the potential of utilizing RNAi to study gene function. Duplexes of 21-nucleotide short interfering dsRNA (siRNA) inhibit gene expression by RNAi. In some organisms, siRNA can als...
متن کاملمهار بیان ژن GFP به وسیله تداخل RNA (RNAi) در دودمان سلولی کارسینومای جنینی P19
Introduction: RNA interference (RNAi) is a phenomenon of gene silencing that uses double-stranded RNA (dsRNA), specifically inhibits gene expression by degrading mRNA efficiently. The mediators of degradation are 21- to 23-nt small interfering RNAs (siRNA). The use of siRNAs as inhibitors of gene expression has been shown to be an effective way of studying gene function in mammalian cells. Ai...
متن کاملO-6: Maturation of Spermatogenic Cells in Artificial Seminiferous Tubules
Background This study aimed to investigate whether Artificial Seminiferous Tubules (AST) coated with testicular extra cellular matrix (ECM) support maturation of spermatogenic cells from immature testes. MaterialsAndMethods Medical grade tubes coated with testicular ECM were used. Testes from immature mice were loaded in the concentration of 10000- 20000/ml. Tubes were then immersed in germ cel...
متن کاملIdentification of Spata-19 New Variant with Expression beyond Meiotic Phase of Mouse Testis Development
Background: The study of specific genes expressed in the testis is important to understanding testis development and function. Spermatogenesis is an attractive model for the study of gene expression during germ cell differentiation. Spermatogenesis associated-19 (Spata-19) is a recently-identified important spermatogenesis-related gene specifically expressed in testis. Its protein product is in...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Mechanisms of Development
دوره 106 شماره
صفحات -
تاریخ انتشار 2001